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More draft documentation.

This commit is contained in:
Philip.Hazel 2014-09-28 17:39:28 +00:00
parent 22fafb8a6f
commit e15b64ef03
16 changed files with 4754 additions and 43 deletions
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46
Makefile.am
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@ -6,29 +6,31 @@ AM_CPPFLAGS = -I$(builddir)/src -I$(srcdir)/src
## Specify the documentation files that are distributed.
# FIXME
dist_doc_DATA = \
AUTHORS \
COPYING \
ChangeLog \
LICENCE \
README
# doc/pcre.txt \
# doc/pcre-config.txt \
# doc/pcregrep.txt \
# doc/pcretest.txt \
# NEWS
NEWS \
README \
doc/pcre2.txt \
doc/pcre2-config.txt \
doc/pcre2grep.txt \
doc/pcre2test.txt
# FIXME
#dist_html_DATA = \
# doc/html/NON-AUTOTOOLS-BUILD.txt \
# doc/html/README.txt \
# doc/html/index.html \
# doc/html/pcre-config.html \
dist_html_DATA = \
doc/html/NON-AUTOTOOLS-BUILD.txt \
doc/html/README.txt \
doc/html/index.html \
doc/html/pcre2-config.html \
doc/html/pcre2api.html \
doc/html/pcre2callout.html \
doc/html/pcre2demo.html \
doc/html/pcre2test.html \
doc/html/pcre2unicode.html
# doc/html/pcre.html \
# doc/html/pcre16.html \
# doc/html/pcre32.html \
# doc/html/pcre_assign_jit_stack.html \
# doc/html/pcre_compile.html \
# doc/html/pcre_compile2.html \
@ -56,11 +58,8 @@ dist_doc_DATA = \
# doc/html/pcre_utf16_to_host_byte_order.html \
# doc/html/pcre_utf32_to_host_byte_order.html \
# doc/html/pcre_version.html \
# doc/html/pcreapi.html \
# doc/html/pcrebuild.html \
# doc/html/pcrecallout.html \
# doc/html/pcrecompat.html \
# doc/html/pcredemo.html \
# doc/html/pcregrep.html \
# doc/html/pcrejit.html \
# doc/html/pcrelimits.html \
@ -72,18 +71,16 @@ dist_doc_DATA = \
# doc/html/pcreprecompile.html \
# doc/html/pcresample.html \
# doc/html/pcrestack.html \
# doc/html/pcresyntax.html \
# doc/html/pcretest.html \
# doc/html/pcreunicode.html
# doc/html/pcresyntax.html
# FIXME
dist_man_MANS = \
doc/pcre2-config.1 \
doc/pcre2api.3 \
doc/pcre2callout.3 \
doc/pcre2test.1 \
doc/pcre2unicode.3
# doc/pcre2-config.1 \
# doc/pcre2.3 \
# doc/pcre2-16.3 \
# doc/pcre2-32.3 \
@ -168,7 +165,6 @@ EXTRA_DIST += \
EXTRA_DIST += \
doc/perltest.txt \
NON-UNIX-USE \
NON-AUTOTOOLS-BUILD \
HACKING
@ -719,9 +715,9 @@ else
coverage:
@echo "Configuring with --enable-coverage is required to generate code coverage report."
DISTCLEANFILES += src/*.gcda src/*.gcno
DISTCLEANFILES += src/*.gcda src/*.gcno
distclean-local:
distclean-local:
rm -rf $(PACKAGE)-$(VERSION)-coverage*
endif # WITH_GCOV

16
PrepareRelease
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@ -83,8 +83,7 @@ for file in pcre2api pcre2callout pcre2unicode ; do
done
# The three commands
for file in pcre2test ; do
# for file in pcre2test pcre2grep pcre-config ; do
for file in pcre2test pcre2grep pcre2-config ; do
echo Making $file.txt
nroff -c -man $file.1 >$file.rawtxt
perl ../CleanTxt <$file.rawtxt >$file.txt
@ -133,7 +132,7 @@ echo "Making HTML documentation"
/bin/rm html/*
cp index.html.src html/index.html
cp ../README html/README.txt
# cp ../NON-AUTOTOOLS-BUILD html/NON-AUTOTOOLS-BUILD.txt
cp ../NON-AUTOTOOLS-BUILD html/NON-AUTOTOOLS-BUILD.txt
for file in *.1 ; do
base=`basename $file .1`
@ -187,7 +186,6 @@ files="\
COPYING \
AUTHORS \
NEWS \
NON-UNIX-USE \
NON-AUTOTOOLS-BUILD \
INSTALL \
132html \
@ -240,16 +238,6 @@ files="\
pcre32_utf32_utils.c \
pcre16_valid_utf16.c \
pcre32_valid_utf32.c \
pcre_scanner.cc \
pcre_scanner.h \
pcre_scanner_unittest.cc \
pcrecpp.cc \
pcrecpp.h \
pcrecpparg.h.in \
pcrecpp_unittest.cc \
pcre_stringpiece.cc \
pcre_stringpiece.h.in \
pcre_stringpiece_unittest.cc \
perltest.pl \
ucp.h \
makevp.bat \

402
doc/html/NON-AUTOTOOLS-BUILD.txt Normal file
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@ -0,0 +1,402 @@
Building PCRE2 without using autotools
--------------------------------------
This document has been converted from the PCRE1 document, but is not yet
complete. I have removed a number of quite old sections about building in
various environments, as they applied only to PCRE1 and are probably out of
date.
This document contains the following sections:
General
Generic instructions for the PCRE2 C library
Building for virtual Pascal
Stack size in Windows environments
Linking programs in Windows environments
Calling conventions in Windows environments
Comments about Win32 builds
Building PCRE2 on Windows with CMake
Testing with RunTest.bat
Building PCRE2 on native z/OS and z/VM
GENERAL
I (Philip Hazel) have no experience of Windows or VMS sytems and how their
libraries work. The items in the PCRE2 distribution and Makefile that relate to
anything other than Linux systems are untested by me.
The basic PCRE2 library consists entirely of code written in Standard C, and so
should compile successfully on any system that has a Standard C compiler and
library.
The PCRE2 distribution includes a "configure" file for use by the
configure/make (autotools) build system, as found in many Unix-like
environments. The README file contains information about the options for
"configure".
There is also support for CMake, which some users prefer, especially in Windows
environments, though it can also be run in Unix-like environments. See the
section entitled "Building PCRE2 on Windows with CMake" below.
Versions of src/config.h and src/pcre2.h are distributed in the PCRE2 tarballs
under the names src/config.h.generic and src/pcre2.h.generic. These are
provided for those who build PCRE2 without using "configure" or CMake. If you
use "configure" or CMake, the .generic versions are not used.
GENERIC INSTRUCTIONS FOR THE PCRE2 C LIBRARY
The following are generic instructions for building the PCRE2 C library "by
hand". If you are going to use CMake, this section does not apply to you; you
can skip ahead to the CMake section.
(1) Copy or rename the file src/config.h.generic as src/config.h, and edit the
macro settings that it contains to whatever is appropriate for your
environment. In particular, you can alter the definition of the NEWLINE
macro to specify what character(s) you want to be interpreted as line
terminators.
When you compile any of the PCRE2 modules, you must specify
-DHAVE_CONFIG_H to your compiler so that src/config.h is included in the
sources.
An alternative approach is not to edit src/config.h, but to use -D on the
compiler command line to make any changes that you need to the
configuration options. In this case -DHAVE_CONFIG_H must not be set.
NOTE: There have been occasions when the way in which certain parameters
in src/config.h are used has changed between releases. (In the
configure/make world, this is handled automatically.) When upgrading to a
new release, you are strongly advised to review src/config.h.generic
before re-using what you had previously.
(2) Copy or rename the file src/pcre2.h.generic as src/pcre2.h.
(3) EITHER:
Copy or rename file src/pcre2_chartables.c.dist as
src/pcre2_chartables.c.
OR:
Compile src/dftables.c as a stand-alone program (using -DHAVE_CONFIG_H
if you have set up src/config.h), and then run it with the single
argument "src/pcre2_chartables.c". This generates a set of standard
character tables and writes them to that file. The tables are generated
using the default C locale for your system. If you want to use a locale
that is specified by LC_xxx environment variables, add the -L option to
the dftables command. You must use this method if you are building on a
system that uses EBCDIC code.
The tables in src/pcre2_chartables.c are defaults. The caller of PCRE2 can
specify alternative tables at run time.
(4) For an 8-bit library, compile the following source files, setting
-DPCRE2_CODE_UNIT_WIDTH=8 as a compiler option. Also set -DHAVE_CONFIG_H
if you have set up src/config.h with your configuration, or else use other
-D settings to change the configuration as required.
pcre2_auto_possess.c
pcre2_chartables.c
pcre2_compile.c
pcre2_config.c
pcre2_context.c
pcre2_dfa_match.c
pcre2_error.c
pcre2_jit_compile.c
pcre2_jit_match.c
pcre2_jit_misc.c
pcre2_maketables.c
pcre2_match.c
pcre2_match_data.c
pcre2_newline.c
pcre2_ord2utf.c
pcre2_pattern_info.c
pcre2_string_utils.c
pcre2_study.c
pcre2_substring.c
pcre2_tables.c
pcre2_ucd.c
pcre2_valid_utf.c
pcre2_xclass.c
Make sure that you include -I. in the compiler command (or equivalent for
an unusual compiler) so that all included PCRE2 header files are first
sought in the src directory under the current directory. Otherwise you run
the risk of picking up a previously-installed file from somewhere else.
Note that you must compile pcre2_jit_xxx.c, even if you have not defined
SUPPORT_JIT in src/config.h, because when JIT support is not configured,
dummy functions are compiled. When JIT support IS configured, the JIT
sources #include other files from the sljit subdirectory, where there
should be 16 files, all of whose names begin with "sljit".
(5) Now link all the compiled code into an object library in whichever form
your system keeps such libraries. This is the basic PCRE2 C 8-bit library.
If your system has static and shared libraries, you may have to do this
once for each type.
(6) If you want to build a 16-bit library or 32-bit library (as well as, or
instead of the 8-bit library) just supply 16 or 32 as the value of
-DPCRE2_CODE_UNIT_WIDTH when you are compiling.
(7) If you want to build the POSIX wrapper functions (which apply only to the
8-bit library), ensure that you have the pcre2posix.h file and then
compile pcre2posix.c. Link the result (on its own) as the pcre2posix
library.
(8) The pcre2test program can be linked with any combination of the 8-bit,
16-bit and 32-bit libraries (depending on what you selected in
src/config.h). Compile pcre2test.c; don't forget -DHAVE_CONFIG_H if
necessary, but do NOT define PCRE2_CODE_UNIT_WIDTH. Then link with the
appropriate library/ies. If you compiled an 8-bit library, pcre2test also
needs the pcre2posix wrapper library.
(9) Run pcre2test on the testinput files in the testdata directory, and check
that the output matches the corresponding testoutput files. There are
comments about what each test does in the section entitled "Testing PCRE2"
in the README file. If you compiled more than one of the 8-bit, 16-bit and
32-bit libraries, you need to run pcre2test with the -16 option to do
16-bit tests and with the -32 option to do 32-bit tests.
Some tests are relevant only when certain build-time options are selected.
For example, test 4 is for Unicode support, and will not run if you have
built PCRE2 without it. See the comments at the start of each testinput
file. If you have a suitable Unix-like shell, the RunTest script will run
the appropriate tests for you. The command "RunTest list" will output a
list of all the tests.
Note that the supplied files are in Unix format, with just LF characters
as line terminators. You may need to edit them to change this if your
system uses a different convention.
(10) If you have built PCRE2 with SUPPORT_JIT, the JIT features can be tested
by running pcre2test with the -jit option. This is done automatically by
the RunTest script. You might also like to build and run the freestanding
JIT test program, pcre2_jit_test.c.
(11) If you want to use the pcre2grep command, compile and link pcre2grep.c; it
uses only the basic 8-bit PCRE2 library (it does not need the pcre2posix
library).
BUILDING FOR VIRTUAL PASCAL
FIXME FOR PCRE2
A script for building PCRE2 using Borland's C++ compiler for use with VPASCAL
was contributed by Alexander Tokarev. Stefan Weber updated the script and added
additional files. The following files in the distribution are for building
PCRE2 for use with VP/Borland: makevp_c.txt, makevp_l.txt, makevp.bat,
pcre2gexp.pas.
STACK SIZE IN WINDOWS ENVIRONMENTS
The default processor stack size of 1Mb in some Windows environments is too
small for matching patterns that need much recursion. In particular, test 2 may
fail because of this. Normally, running out of stack causes a crash, but there
have been cases where the test program has just died silently. See your linker
documentation for how to increase stack size if you experience problems. The
Linux default of 8Mb is a reasonable choice for the stack, though even that can
be too small for some pattern/subject combinations.
PCRE2 has a compile configuration option to disable the use of stack for
recursion so that heap is used instead. However, pattern matching is
significantly slower when this is done. There is more about stack usage in the
"pcre2stack" documentation.
LINKING PROGRAMS IN WINDOWS ENVIRONMENTS
If you want to statically link a program against a PCRE2 library in the form of
a non-dll .a file, you must define PCRE2_STATIC before including src/pcre2.h.
CALLING CONVENTIONS IN WINDOWS ENVIRONMENTS
It is possible to compile programs to use different calling conventions using
MSVC. Search the web for "calling conventions" for more information. To make it
easier to change the calling convention for the exported functions in the
PCRE2 library, the macro PCRE2_CALL_CONVENTION is present in all the external
definitions. It can be set externally when compiling (e.g. in CFLAGS). If it is
not set, it defaults to empty; the default calling convention is then used
(which is what is wanted most of the time).
COMMENTS ABOUT WIN32 BUILDS (see also "BUILDING PCRE2 ON WINDOWS WITH CMAKE")
There are two ways of building PCRE2 using the "configure, make, make install"
paradigm on Windows systems: using MinGW or using Cygwin. These are not at all
the same thing; they are completely different from each other. There is also
support for building using CMake, which some users find a more straightforward
way of building PCRE2 under Windows.
The MinGW home page (http://www.mingw.org/) says this:
MinGW: A collection of freely available and freely distributable Windows
specific header files and import libraries combined with GNU toolsets that
allow one to produce native Windows programs that do not rely on any
3rd-party C runtime DLLs.
The Cygwin home page (http://www.cygwin.com/) says this:
Cygwin is a Linux-like environment for Windows. It consists of two parts:
. A DLL (cygwin1.dll) which acts as a Linux API emulation layer providing
substantial Linux API functionality
. A collection of tools which provide Linux look and feel.
On both MinGW and Cygwin, PCRE2 should build correctly using:
./configure && make && make install
This should create two libraries called libpcre2-8 and libpcre2-posix. These
are independent libraries: when you link with libpcre2-posix you must also link
with libpcre2-8, which contains the basic functions.
Using Cygwin's compiler generates libraries and executables that depend on
cygwin1.dll. If a library that is generated this way is distributed,
cygwin1.dll has to be distributed as well. Since cygwin1.dll is under the GPL
licence, this forces not only PCRE2 to be under the GPL, but also the entire
application. A distributor who wants to keep their own code proprietary must
purchase an appropriate Cygwin licence.
MinGW has no such restrictions. The MinGW compiler generates a library or
executable that can run standalone on Windows without any third party dll or
licensing issues.
But there is more complication:
If a Cygwin user uses the -mno-cygwin Cygwin gcc flag, what that really does is
to tell Cygwin's gcc to use the MinGW gcc. Cygwin's gcc is only acting as a
front end to MinGW's gcc (if you install Cygwin's gcc, you get both Cygwin's
gcc and MinGW's gcc). So, a user can:
. Build native binaries by using MinGW or by getting Cygwin and using
-mno-cygwin.
. Build binaries that depend on cygwin1.dll by using Cygwin with the normal
compiler flags.
The test files that are supplied with PCRE2 are in UNIX format, with LF
characters as line terminators. Unless your PCRE2 library uses a default
newline option that includes LF as a valid newline, it may be necessary to
change the line terminators in the test files to get some of the tests to work.
BUILDING PCRE2 ON WINDOWS WITH CMAKE
CMake is an alternative configuration facility that can be used instead of
"configure". CMake creates project files (make files, solution files, etc.)
tailored to numerous development environments, including Visual Studio,
Borland, Msys, MinGW, NMake, and Unix. If possible, use short paths with no
spaces in the names for your CMake installation and your PCRE2 source and build
directories.
The following instructions were contributed by a PCRE1 user, but they should
also work for PCRE2. If they are not followed exactly, errors may occur. In the
event that errors do occur, it is recommended that you delete the CMake cache
before attempting to repeat the CMake build process. In the CMake GUI, the
cache can be deleted by selecting "File > Delete Cache".
1. Install the latest CMake version available from http://www.cmake.org/, and
ensure that cmake\bin is on your path.
2. Unzip (retaining folder structure) the PCRE2 source tree into a source
directory such as C:\pcre2. You should ensure your local date and time
is not earlier than the file dates in your source dir if the release is
very new.
3. Create a new, empty build directory, preferably a subdirectory of the
source dir. For example, C:\pcre2\pcre2-xx\build.
4. Run cmake-gui from the Shell envirornment of your build tool, for example,
Msys for Msys/MinGW or Visual Studio Command Prompt for VC/VC++. Do not try
to start Cmake from the Windows Start menu, as this can lead to errors.
5. Enter C:\pcre2\pcre2-xx and C:\pcre2\pcre2-xx\build for the source and
build directories, respectively.
6. Hit the "Configure" button.
7. Select the particular IDE / build tool that you are using (Visual
Studio, MSYS makefiles, MinGW makefiles, etc.)
8. The GUI will then list several configuration options. This is where
you can enable Unicode support or other PCRE2 optional features.
9. Hit "Configure" again. The adjacent "Generate" button should now be
active.
10. Hit "Generate".
11. The build directory should now contain a usable build system, be it a
solution file for Visual Studio, makefiles for MinGW, etc. Exit from
cmake-gui and use the generated build system with your compiler or IDE.
E.g., for MinGW you can run "make", or for Visual Studio, open the PCRE2
solution, select the desired configuration (Debug, or Release, etc.) and
build the ALL_BUILD project.
12. If during configuration with cmake-gui you've elected to build the test
programs, you can execute them by building the test project. E.g., for
MinGW: "make check"; for Visual Studio build the RUN_TESTS project. The
most recent build configuration is targeted by the tests. A summary of
test results is presented. Complete test output is subsequently
available for review in Testing\Temporary under your build dir.
TESTING WITH RUNTEST.BAT FIXME FIXME NOT YET TESTED/UPDATED FIXME
If configured with CMake, building the test project ("make check" or building
ALL_TESTS in Visual Studio) creates (and runs) pcre2_test.bat (and depending
on your configuration options, possibly other test programs) in the build
directory. Pcre_test.bat runs RunTest.Bat with correct source and exe paths.
For manual testing with RunTest.bat, provided the build dir is a subdirectory
of the source directory: Open command shell window. Chdir to the location
of your pcre2test.exe and pcre2grep.exe programs. Call RunTest.bat with
"..\RunTest.Bat" or "..\..\RunTest.bat" as appropriate.
To run only a particular test with RunTest.Bat provide a test number argument.
Otherwise:
1. Copy RunTest.bat into the directory where pcre2test.exe and pcre2grep.exe
have been created.
2. Edit RunTest.bat to indentify the full or relative location of
the pcre2 source (wherein which the testdata folder resides), e.g.:
set srcdir=C:\pcre2\pcre2-10.00
3. In a Windows command environment, chdir to the location of your bat and
exe programs.
4. Run RunTest.bat. Test outputs will automatically be compared to expected
results, and discrepancies will be identified in the console output.
To independently test the just-in-time compiler, run pcre2_jit_test.exe.
BUILDING PCRE2 ON NATIVE Z/OS AND Z/VM
z/OS and z/VM are operating systems for mainframe computers, produced by IBM.
The character code used is EBCDIC, not ASCII or Unicode. In z/OS, UNIX APIs and
applications can be supported through UNIX System Services, and in such an
environment PCRE2 can be built in the same way as in other systems. However, in
native z/OS (without UNIX System Services) and in z/VM, special ports are
required. For details, please see this web site:
http://www.zaconsultants.net
There is also a mirror here:
http://www.vsoft-software.com/downloads.html
The site currently has ports for PCRE1 releases, but PCRE2 should follow in due
course.
==========================
Last Updated: 28 September 2014

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doc/html/README.txt
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@ -1 +1,832 @@
This is a placeholder README file for a work in progress.
README file for PCRE2 (Perl-compatible regular expression library)
------------------------------------------------------------------
PCRE2 is a re-implementation of the original PCRE library with an entirely new
API. The latest release of PCRE2 is always available in three alternative
formats from:
FIXME: THIS WILL NOT BE THE CASE UNTIL THERE IS A FORMAL RELEASE.
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre2/pcre2-xxx.tar.gz
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre2/pcre2-xxx.tar.bz2
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre2/pcre2-xxx.zip
There is a mailing list for discussion about the development of PCRE (both the
original and new APIs) at pcre-dev@exim.org. You can access the archives and
subscribe or manage your subscription here:
https://lists.exim.org/mailman/listinfo/pcre-dev
Please read the NEWS file if you are upgrading from a previous release.
The contents of this README file are:
The PCRE2 APIs
Documentation for PCRE2
Contributions by users of PCRE2
Building PCRE2 on non-Unix-like systems
Building PCRE2 without using autotools
Building PCRE2 using autotools
Retrieving configuration information
Shared libraries
Cross-compiling using autotools
Making new tarballs
Testing PCRE2
Character tables
File manifest
The PCRE2 APIs
--------------
PCRE2 is written in C, and it has its own API. There are three sets of
functions, one for the 8-bit library, which processes strings of bytes, one for
the 16-bit library, which processes strings of 16-bit values, and one for the
32-bit library, which processes strings of 32-bit values. As this is a new API,
there as yet no C++ wrappers.
The distribution does contain a set of C wrapper functions for the 8-bit
library that are based on the POSIX regular expression API (see the pcre2posix
man page). These end up in the library called libpcre2posix. Note that this
just provides a POSIX calling interface to PCRE2; the regular expressions
themselves still follow Perl syntax and semantics. The POSIX API is restricted,
and does not give full access to all of PCRE2's facilities.
The header file for the POSIX-style functions is called pcre2posix.h. The
official POSIX name is regex.h, but I did not want to risk possible problems
with existing files of that name by distributing it that way. To use PCRE2 with
an existing program that uses the POSIX API, pcre2posix.h will have to be
renamed or pointed at by a link.
If you are using the POSIX interface to PCRE2 and there is already a POSIX
regex library installed on your system, as well as worrying about the regex.h
header file (as mentioned above), you must also take care when linking programs
to ensure that they link with PCRE2's libpcre2posix library. Otherwise they may
pick up the POSIX functions of the same name from the other library.
One way of avoiding this confusion is to compile PCRE2 with the addition of
-Dregcomp=PCRE2regcomp (and similarly for the other POSIX functions) to the
compiler flags (CFLAGS if you are using "configure" -- see below). This has the
effect of renaming the functions so that the names no longer clash. Of course,
you have to do the same thing for your applications, or write them using the
new names.
Documentation for PCRE2
----------------------
If you install PCRE2 in the normal way on a Unix-like system, you will end up
with a set of man pages whose names all start with "pcre2". The one that is
just called "pcre2" lists all the others. In addition to these man pages, the
PCRE2 documentation is supplied in two other forms:
1. There are files called doc/pcre2.txt, doc/pcre2grep.txt, and
doc/pcre2test.txt in the source distribution. The first of these is a
concatenation of the text forms of all the section 3 man pages except the
listing of pcre2demo.c and those that summarize individual functions. The
other two are the text forms of the section 1 man pages for the pcre2grep
and pcre2test commands. These text forms are provided for ease of scanning
with text editors or similar tools. They are installed in
<prefix>/share/doc/pcre2, where <prefix> is the installation prefix
(defaulting to /usr/local).
2. A set of files containing all the documentation in HTML form, hyperlinked
in various ways, and rooted in a file called index.html, is distributed in
doc/html and installed in <prefix>/share/doc/pcre2/html.
Building PCRE2 on non-Unix-like systems
--------------------------------------
For a non-Unix-like system, please read the comments in the file
NON-AUTOTOOLS-BUILD, though if your system supports the use of "configure" and
"make" you may be able to build PCRE2 using autotools in the same way as for
many Unix-like systems.
PCRE2 can also be configured using CMake, which can be run in various ways
(command line, GUI, etc). This creates Makefiles, solution files, etc. The file
NON-AUTOTOOLS-BUILD has information about CMake.
PCRE2 has been compiled on many different operating systems. It should be
straightforward to build PCRE2 on any system that has a Standard C compiler and
library, because it uses only Standard C functions.
Building PCRE2 without using autotools
-------------------------------------
The use of autotools (in particular, libtool) is problematic in some
environments, even some that are Unix or Unix-like. See the NON-AUTOTOOLS-BUILD
file for ways of building PCRE2 without using autotools.
Building PCRE2 using autotools
-----------------------------
The following instructions assume the use of the widely used "configure; make;
make install" (autotools) process.
To build PCRE2 on system that supports autotools, first run the "configure"
command from the PCRE2 distribution directory, with your current directory set
to the directory where you want the files to be created. This command is a
standard GNU "autoconf" configuration script, for which generic instructions
are supplied in the file INSTALL.
Most commonly, people build PCRE2 within its own distribution directory, and in
this case, on many systems, just running "./configure" is sufficient. However,
the usual methods of changing standard defaults are available. For example:
CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
This command specifies that the C compiler should be run with the flags '-O2
-Wall' instead of the default, and that "make install" should install PCRE2
under /opt/local instead of the default /usr/local.
If you want to build in a different directory, just run "configure" with that
directory as current. For example, suppose you have unpacked the PCRE2 source
into /source/pcre2/pcre2-xxx, but you want to build it in
/build/pcre2/pcre2-xxx:
cd /build/pcre2/pcre2-xxx
/source/pcre2/pcre2-xxx/configure
PCRE2 is written in C and is normally compiled as a C library. However, it is
possible to build it as a C++ library, though the provided building apparatus
does not have any features to support this.
There are some optional features that can be included or omitted from the PCRE2
library. They are also documented in the pcre2build man page.
. By default, both shared and static libraries are built. You can change this
by adding one of these options to the "configure" command:
--disable-shared
--disable-static
(See also "Shared libraries on Unix-like systems" below.)
. By default, only the 8-bit library is built. If you add --enable-pcre16 to
the "configure" command, the 16-bit library is also built. If you add
--enable-pcre32 to the "configure" command, the 32-bit library is also built.
If you want only the 16-bit or 32-bit library, use --disable-pcre8 to disable
building the 8-bit library.
. If you want to include support for just-in-time compiling, which can give
large performance improvements on certain platforms, add --enable-jit to the
"configure" command. This support is available only for certain hardware
architectures. If you try to enable it on an unsupported architecture, there
will be a compile time error. FIXME: NOT YET IMPLEMENTED.
. When JIT support is enabled, pcre2grep automatically makes use of it, unless
you add --disable-pcre2grep-jit to the "configure" command.
. If you want to make use of the support for UTF-8 Unicode character strings in
the 8-bit library, UTF-16 Unicode character strings in the 16-bit library,
and UTF-32 Unicode character strings in the 32-bit library, you must add
--enable-unicode to the "configure" command. Without it, the code for
handling UTF-8, UTF-16 and UTF-8 is not included. It is not possible to
configure one library with UTF support and the other without in the same
configuration.
Even when --enable-unicode is included, the use of a UTF encoding still has
to be enabled by an option at run time. When PCRE2 is compiled with this
option, its input can only either be ASCII or UTF-8/16/32, even when running
on EBCDIC platforms. It is not possible to use both --enable-unicode and
--enable-ebcdic at the same time.
When --enable-unicode is specified, as well as supporting UTF strings, PCRE2
includes support for the \P, \p, and \X sequences that recognize Unicode
character properties. However, only the basic two-letter properties such as
Lu are supported.
. You can build PCRE2 to recognize either CR or LF or the sequence CRLF or any
of the preceding, or any of the Unicode newline sequences as indicating the
end of a line. Whatever you specify at build time is the default; the caller
of PCRE2 can change the selection at run time. The default newline indicator
is a single LF character (the Unix standard). You can specify the default
newline indicator by adding --enable-newline-is-cr or --enable-newline-is-lf
or --enable-newline-is-crlf or --enable-newline-is-anycrlf or
--enable-newline-is-any to the "configure" command, respectively.
If you specify --enable-newline-is-cr or --enable-newline-is-crlf, some of
the standard tests will fail, because the lines in the test files end with
LF. Even if the files are edited to change the line endings, there are likely
to be some failures. With --enable-newline-is-anycrlf or
--enable-newline-is-any, many tests should succeed, but there may be some
failures.
. By default, the sequence \R in a pattern matches any Unicode line ending
sequence. This is independent of the option specifying what PCRE2 considers
to be the end of a line (see above). However, the caller of PCRE2 can
restrict \R to match only CR, LF, or CRLF. You can make this the default by
adding --enable-bsr-anycrlf to the "configure" command (bsr = "backslash R").
. PCRE2 has a counter that limits the depth of nesting of parentheses in a
pattern. This limits the amount of system stack that a pattern uses when it
is compiled. The default is 250, but you can change it by setting, for
example,
--with-parens-nest-limit=500
. PCRE2 has a counter that can be set to limit the amount of resources it uses
when matching a pattern. If the limit is exceeded during a match, the match
fails. The default is ten million. You can change the default by setting, for
example,
--with-match-limit=500000
on the "configure" command. This is just the default; individual calls to
pcre2_match() can supply their own value. There is more discussion on the
pcre2api man page.
. There is a separate counter that limits the depth of recursive function calls
during a matching process. This also has a default of ten million, which is
essentially "unlimited". You can change the default by setting, for example,
--with-match-limit-recursion=500000
Recursive function calls use up the runtime stack; running out of stack can
cause programs to crash in strange ways. There is a discussion about stack
sizes in the pcre2stack man page.
. In the 8-bit library, the default maximum compiled pattern size is around
64K. You can increase this by adding --with-link-size=3 to the "configure"
command. PCRE2 then uses three bytes instead of two for offsets to different
parts of the compiled pattern. In the 16-bit library, --with-link-size=3 is
the same as --with-link-size=4, which (in both libraries) uses four-byte
offsets. Increasing the internal link size reduces performance. In the 32-bit
library, the link size setting is ignored, as 4-byte offsets are always used.
. You can build PCRE2 so that its internal match() function that is called from
pcre2_match() does not call itself recursively. Instead, it uses memory
blocks obtained from the heap to save data that would otherwise be saved on
the stack. To build PCRE2 like this, use
--disable-stack-for-recursion
on the "configure" command. PCRE2 runs more slowly in this mode, but it may
be necessary in environments with limited stack sizes. This applies only to
the normal execution of the pcre2_match() function; if JIT support is being
successfully used, it is not relevant. Equally, it does not apply to
pcre2_dfa_match(), which does not use deeply nested recursion. There is a
discussion about stack sizes in the pcre2stack man page.
. For speed, PCRE2 uses four tables for manipulating and identifying characters
whose code point values are less than 256. By default, it uses a set of
tables for ASCII encoding that is part of the distribution. If you specify
--enable-rebuild-chartables
a program called dftables is compiled and run in the default C locale when
you obey "make". It builds a source file called pcre2_chartables.c. If you do
not specify this option, pcre2_chartables.c is created as a copy of
pcre2_chartables.c.dist. See "Character tables" below for further
information.
. It is possible to compile PCRE2 for use on systems that use EBCDIC as their
character code (as opposed to ASCII/Unicode) by specifying
--enable-ebcdic
This automatically implies --enable-rebuild-chartables (see above). However,
when PCRE2 is built this way, it always operates in EBCDIC. It cannot support
both EBCDIC and UTF-8/16/32. There is a second option, --enable-ebcdic-nl25,
which specifies that the code value for the EBCDIC NL character is 0x25
instead of the default 0x15.
. In environments where valgrind is installed, if you specify
--enable-valgrind
PCRE2 will use valgrind annotations to mark certain memory regions as
unaddressable. This allows it to detect invalid memory accesses, and is
mostly useful for debugging PCRE2 itself.
. In environments where the gcc compiler is used and lcov version 1.6 or above
is installed, if you specify
--enable-coverage
the build process implements a code coverage report for the test suite. The
report is generated by running "make coverage". If ccache is installed on
your system, it must be disabled when building PCRE2 for coverage reporting.
You can do this by setting the environment variable CCACHE_DISABLE=1 before
running "make" to build PCRE2. There is more information about coverage
reporting in the "pcre2build" documentation.
. The pcre2grep program currently supports only 8-bit data files, and so
requires the 8-bit PCRE2 library. It is possible to compile pcre2grep to use
libz and/or libbz2, in order to read .gz and .bz2 files (respectively), by
specifying one or both of
--enable-pcre2grep-libz
--enable-pcre2grep-libbz2
Of course, the relevant libraries must be installed on your system.
. The default size (in bytes) of the internal buffer used by pcre2grep can be
set by, for example:
--with-pcre2grep-bufsize=51200
The value must be a plain integer. The default is 20480.
. It is possible to compile pcre2test so that it links with the libreadline
or libedit libraries, by specifying, respectively,
--enable-pcre2test-libreadline or --enable-pcre2test-libedit
If this is done, when pcre2test's input is from a terminal, it reads it using
the readline() function. This provides line-editing and history facilities.
Note that libreadline is GPL-licenced, so if you distribute a binary of
pcre2test linked in this way, there may be licensing issues. These can be
avoided by linking with libedit (which has a BSD licence) instead.
Enabling libreadline causes the -lreadline option to be added to the
pcre2test build. In many operating environments with a sytem-installed
readline library this is sufficient. However, in some environments (e.g. if
an unmodified distribution version of readline is in use), it may be
necessary to specify something like LIBS="-lncurses" as well. This is
because, to quote the readline INSTALL, "Readline uses the termcap functions,
but does not link with the termcap or curses library itself, allowing
applications which link with readline the to choose an appropriate library."
If you get error messages about missing functions tgetstr, tgetent, tputs,
tgetflag, or tgoto, this is the problem, and linking with the ncurses library
should fix it.
The "configure" script builds the following files for the basic C library:
. Makefile the makefile that builds the library
. src/config.h build-time configuration options for the library
. src/pcre2.h the public PCRE2 header file
. pcre2-config script that shows the building settings such as CFLAGS
that were set for "configure"
. libpcre2-8.pc )
. libpcre2-16.pc ) data for the pkg-config command
. libpcre2-32.pc )
. libpcre2-posix.pc )
. libtool script that builds shared and/or static libraries
Versions of config.h and pcre2.h are distributed in the src directory of PCRE2
tarballs under the names config.h.generic and pcre2.h.generic. These are
provided for those who have to build PCRE2 without using "configure" or CMake.
If you use "configure" or CMake, the .generic versions are not used.
The "configure" script also creates config.status, which is an executable
script that can be run to recreate the configuration, and config.log, which
contains compiler output from tests that "configure" runs.
Once "configure" has run, you can run "make". This builds whichever of the
libraries libpcre2-8, libpcre2-16 and libpcre2-32 are configured, and a test
program called pcre2test. If you enabled JIT support with --enable-jit, another
test program called pcre2_jit_test is built as well. FIXME: still to be
implemented. If the 8-bit library is built, libpcre2-posix and the pcre2grep
command are also built.
The command "make check" runs all the appropriate tests. Details of the PCRE2
tests are given below in a separate section of this document.
You can use "make install" to install PCRE2 into live directories on your
system. The following are installed (file names are all relative to the
<prefix> that is set when "configure" is run):
Commands (bin):
pcre2test
pcre2grep (if 8-bit support is enabled)
pcre2-config
Libraries (lib):
libpcre2-8 (if 8-bit support is enabled)
libpcre2-16 (if 16-bit support is enabled)
libpcre2-32 (if 32-bit support is enabled)
libpcre2-posix (if 8-bit support is enabled)
Configuration information (lib/pkgconfig):
libpcre2-8.pc
libpcre2-16.pc
libpcre2-32.pc
libpcre2-posix.pc
Header files (include):
pcre2.h
pcre2posix.h
Man pages (share/man/man{1,3}):
pcre2grep.1
pcre2test.1
pcre2-config.1
pcre2.3
pcre2*.3 (lots more pages, all starting "pcre2")
HTML documentation (share/doc/pcre2/html):
index.html
*.html (lots more pages, hyperlinked from index.html)
Text file documentation (share/doc/pcre2):
AUTHORS
COPYING
ChangeLog
LICENCE
NEWS
README
pcre2.txt (a concatenation of the man(3) pages)
pcre2test.txt the pcre2test man page
pcre2grep.txt the pcre2grep man page
pcre2-config.txt the pcre2-config man page
If you want to remove PCRE2 from your system, you can run "make uninstall".
This removes all the files that "make install" installed. However, it does not
remove any directories, because these are often shared with other programs.
Retrieving configuration information
------------------------------------
Running "make install" installs the command pcre2-config, which can be used to
recall information about the PCRE2 configuration and installation. For example:
pcre2-config --version
prints the version number, and
pcre2-config --libs8
outputs information about where the 8-bit library is installed. This command
can be included in makefiles for programs that use PCRE2, saving the programmer
from having to remember too many details. Run pcre2-config with no arguments to
obtain a list of possible arguments.
The pkg-config command is another system for saving and retrieving information
about installed libraries. Instead of separate commands for each library, a
single command is used. For example:
pkg-config --libs libpcre2-16
The data is held in *.pc files that are installed in a directory called
<prefix>/lib/pkgconfig.
Shared libraries
----------------
The default distribution builds PCRE2 as shared libraries and static libraries,
as long as the operating system supports shared libraries. Shared library
support relies on the "libtool" script which is built as part of the
"configure" process.
The libtool script is used to compile and link both shared and static
libraries. They are placed in a subdirectory called .libs when they are newly
built. The programs pcre2test and pcre2grep are built to use these uninstalled
libraries (by means of wrapper scripts in the case of shared libraries). When
you use "make install" to install shared libraries, pcre2grep and pcre2test are
automatically re-built to use the newly installed shared libraries before being
installed themselves. However, the versions left in the build directory still
use the uninstalled libraries.
To build PCRE2 using static libraries only you must use --disable-shared when
configuring it. For example:
./configure --prefix=/usr/gnu --disable-shared
Then run "make" in the usual way. Similarly, you can use --disable-static to
build only shared libraries.
Cross-compiling using autotools
-------------------------------
You can specify CC and CFLAGS in the normal way to the "configure" command, in
order to cross-compile PCRE2 for some other host. However, you should NOT
specify --enable-rebuild-chartables, because if you do, the dftables.c source
file is compiled and run on the local host, in order to generate the inbuilt
character tables (the pcre2_chartables.c file). This will probably not work,
because dftables.c needs to be compiled with the local compiler, not the cross
compiler.
When --enable-rebuild-chartables is not specified, pcre2_chartables.c is
created by making a copy of pcre2_chartables.c.dist, which is a default set of
tables that assumes ASCII code. Cross-compiling with the default tables should
not be a problem.
If you need to modify the character tables when cross-compiling, you should
move pcre2_chartables.c.dist out of the way, then compile dftables.c by hand
and run it on the local host to make a new version of pcre2_chartables.c.dist.
Then when you cross-compile PCRE2 this new version of the tables will be used.
Making new tarballs
-------------------
The command "make dist" creates three PCRE2 tarballs, in tar.gz, tar.bz2, and
zip formats. The command "make distcheck" does the same, but then does a trial
build of the new distribution to ensure that it works.
If you have modified any of the man page sources in the doc directory, you
should first run the PrepareRelease script before making a distribution. This
script creates the .txt and HTML forms of the documentation from the man pages.
Testing PCRE2
------------
To test the basic PCRE2 library on a Unix-like system, run the RunTest script.
There is another script called RunGrepTest that tests the options of the
pcre2grep command. When JIT support is enabled, another test program called
pcre2_jit_test is built. Both the scripts and all the program tests are run if
you obey "make check". For other environments, see the instructions in
NON-AUTOTOOLS-BUILD.
The RunTest script runs the pcre2test test program (which is documented in its
own man page) on each of the relevant testinput files in the testdata
directory, and compares the output with the contents of the corresponding
testoutput files. RunTest uses a file called testtry to hold the main output
from pcre2test. Other files whose names begin with "test" are used as working
files in some tests.
Some tests are relevant only when certain build-time options were selected. For
example, the tests for UTF-8/16/32 support are run only if --enable-unicode was
used. RunTest outputs a comment when it skips a test.
Many of the tests that are not skipped are run twice if JIT support is
available. On the second run, JIT compilation is forced. This testing can be
suppressed by putting "nojit" on the RunTest command line.
The entire set of tests is run once for each of the 8-bit, 16-bit and 32-bit
libraries that are enabled. If you want to run just one set of tests, call
RunTest with either the -8, -16 or -32 option.
If valgrind is installed, you can run the tests under it by putting "valgrind"
on the RunTest command line. To run pcre2test on just one or more specific test
files, give their numbers as arguments to RunTest, for example:
RunTest 2 7 11
You can also specify ranges of tests such as 3-6 or 3- (meaning 3 to the
end), or a number preceded by ~ to exclude a test. For example:
Runtest 3-15 ~10
This runs tests 3 to 15, excluding test 10, and just ~13 runs all the tests
except test 13. Whatever order the arguments are in, the tests are always run
in numerical order.
You can also call RunTest with the single argument "list" to cause it to output
a list of tests.
The first two tests can always be run, as they expect only plain text strings
(not UTF) and make no use of Unicode properties. The first test file can be fed
directly into the perltest.pl script to check that Perl gives the same results.
The only difference you should see is in the first few lines, where the Perl
version is given instead of the PCRE2 version. The second set of tests check
auxiliary functions, error detection, and run-time flags that are specific to
PCRE2, as well as the POSIX wrapper API. It also uses the debugging flags to
check some of the internals of pcre2_compile().
If you build PCRE2 with a locale setting that is not the standard C locale, the
character tables may be different (see next paragraph). In some cases, this may
cause failures in the second set of tests. For example, in a locale where the
isprint() function yields TRUE for characters in the range 128-255, the use of
[:isascii:] inside a character class defines a different set of characters, and
this shows up in this test as a difference in the compiled code, which is being
listed for checking. Where the comparison test output contains [\x00-\x7f] the
test will contain [\x00-\xff], and similarly in some other cases. This is not a
bug in PCRE2.
The third set of tests checks pcre2_maketables(), the facility for building a
set of character tables for a specific locale and using them instead of the
default tables. The script uses the "locale" command to check for the
availability of the "fr_FR", "french", or "fr" locale, and uses the first one
that it finds. If the "locale" command fails, or if its output doesn't include
"fr_FR", "french", or "fr" in the list of available locales, the third test
cannot be run, and a comment is output to say why. If running this test
produces an error like this
** Failed to set locale "fr_FR"
it means that the given locale is not available on your system, despite being
listed by "locale". This does not mean that PCRE2 is broken. There are three
alternative output files for the third test, because three different versions
of the French locale have been encountered. The test passes if its output
matches any one of them.
The fourth and fifth tests check UTF and Unicode property support, the fourth
being compatible with the perltest.pl script, and the fifth checking
PCRE2-specific things.
The sixth and seventh tests check the pcre2_dfa_match() alternative matching
function, in non-UTF mode and UTF-mode with Unicode property support,
respectively.
The eighth test checks some internal offsets and code size features; it is
run only when the default "link size" of 2 is set (in other cases the sizes
change) and when Unicode support is enabled.
The ninth and tenth tests are run only in 8-bit mode, and the eleventh and
twelfth tests are run only in 16-bit and 32-bit modes. These are tests that
generate different output in 8-bit mode. Each pair are for general cases and
Unicode support, respectively. The thirteenth test checks the handling of
non-UTF characters greater than 255 by pcre2_dfa_match() in 16-bit and 32-bit
modes.
The fourteenth test is run only when JIT support is not available, and the
fifteenth test is run only when JIT support is available. They test some
JIT-specific features such as information output from pcre2test about JIT
compilation.
The sixteenth and seventeenth tests are run only in 8-bit mode. They check the
POSIX interface to the 8-bit library, withouth and with Unicode support,
respectively.
Character tables
----------------
For speed, PCRE2 uses four tables for manipulating and identifying characters
whose code point values are less than 256. By default, a set of tables that is
built into the library is used. The pcre2_maketables() function can be called
by an application to create a new set of tables in the current locale. This are
passed to PCRE2 by calling pcre2_set_character_tables() to put a pointer into a
compile context.
The source file called pcre2_chartables.c contains the default set of tables.
By default, this is created as a copy of pcre2_chartables.c.dist, which
contains tables for ASCII coding. However, if --enable-rebuild-chartables is
specified for ./configure, a different version of pcre2_chartables.c is built
by the program dftables (compiled from dftables.c), which uses the ANSI C
character handling functions such as isalnum(), isalpha(), isupper(),
islower(), etc. to build the table sources. This means that the default C
locale which is set for your system will control the contents of these default
tables. You can change the default tables by editing pcre2_chartables.c and
then re-building PCRE2. If you do this, you should take care to ensure that the
file does not get automatically re-generated. The best way to do this is to
move pcre2_chartables.c.dist out of the way and replace it with your customized
tables.
When the dftables program is run as a result of --enable-rebuild-chartables,
it uses the default C locale that is set on your system. It does not pay
attention to the LC_xxx environment variables. In other words, it uses the
system's default locale rather than whatever the compiling user happens to have
set. If you really do want to build a source set of character tables in a
locale that is specified by the LC_xxx variables, you can run the dftables
program by hand with the -L option. For example:
./dftables -L pcre2_chartables.c.special
The first two 256-byte tables provide lower casing and case flipping functions,
respectively. The next table consists of three 32-byte bit maps which identify
digits, "word" characters, and white space, respectively. These are used when
building 32-byte bit maps that represent character classes for code points less
than 256. The final 256-byte table has bits indicating various character types,
as follows:
1 white space character
2 letter
4 decimal digit
8 hexadecimal digit
16 alphanumeric or '_'
128 regular expression metacharacter or binary zero
You should not alter the set of characters that contain the 128 bit, as that
will cause PCRE2 to malfunction.
File manifest
-------------
The distribution should contain the files listed below.
(A) Source files for the PCRE2 library functions and their headers are found in
the src directory:
src/dftables.c auxiliary program for building pcre2_chartables.c
when --enable-rebuild-chartables is specified
src/pcre2_chartables.c.dist a default set of character tables that assume
ASCII coding; unless --enable-rebuild-chartables is
specified, used by copying to pcre2_chartables.c
src/pcre2posix.c )
src/pcre2_auto_possess.c )
src/pcre2_compile.c )
src/pcre2_config.c )
src/pcre2_context.c )
src/pcre2_dfa_match.c )
src/pcre2_error.c )
src/pcre2_exec.c )
src/pcre2_jit_compile.c )
src/pcre2_jit_match.c ) sources for the functions in the library,
src/pcre2_jit_misc.c ) and some internal functions that they use
src/pcre2_maketables.c )
src/pcre2_match.c )
src/pcre2_match_data.c )
src/pcre2_newline.c )
src/pcre2_ord2utf.c )
src/pcre2_pattern_info.c )
src/pcre2_string_utils.c )
src/pcre2_study.c )
src/pcre2_substring.c )
src/pcre2_tables.c )
src/pcre2_ucd.c )
src/pcre2_valid_utf.c )
src/pcre2_xclass.c )
src/pcre2_printint.c debugging function that is used by pcre2test,
src/config.h.in template for config.h, when built by "configure"
src/pcre2.h.in template for pcre2.h when built by "configure"
src/pcre2posix.h header for the external POSIX wrapper API
src/pcre2_internal.h header for internal use
src/pcre2_intmodedep.h a mode-specific internal header
src/pcre2_ucp.h header for Unicode property handling
sljit/* 16 files that make up the JIT compiler FIXME
(B) Source files for programs that use PCRE2:
src/pcre2demo.c simple demonstration of coding calls to PCRE2
src/pcre2grep.c source of a grep utility that uses PCRE2
src/pcre2test.c comprehensive test program
(C) Auxiliary files:
132html script to turn "man" pages into HTML
AUTHORS information about the author of PCRE2
ChangeLog log of changes to the code
CleanTxt script to clean nroff output for txt man pages
Detrail script to remove trailing spaces
HACKING some notes about the internals of PCRE2
INSTALL generic installation instructions
LICENCE conditions for the use of PCRE2
COPYING the same, using GNU's standard name
Makefile.in ) template for Unix Makefile, which is built by
) "configure"
Makefile.am ) the automake input that was used to create
) Makefile.in
NEWS important changes in this release
NON-AUTOTOOLS-BUILD notes on building PCRE2 without using autotools
PrepareRelease script to make preparations for "make dist"
README this file
RunTest a Unix shell script for running tests
RunGrepTest a Unix shell script for pcre2grep tests
aclocal.m4 m4 macros (generated by "aclocal")
config.guess ) files used by libtool,
config.sub ) used only when building a shared library
configure a configuring shell script (built by autoconf)
configure.ac ) the autoconf input that was used to build
) "configure" and config.h
depcomp ) script to find program dependencies, generated by
) automake
doc/*.3 man page sources for PCRE2
doc/*.1 man page sources for pcre2grep and pcre2test
doc/index.html.src the base HTML page
doc/html/* HTML documentation
doc/pcre2.txt plain text version of the man pages
doc/pcre2test.txt plain text documentation of test program
doc/perltest.txt plain text documentation of Perl test program
install-sh a shell script for installing files
libpcre2-8.pc.in template for libpcre2-8.pc for pkg-config
libpcre2-16.pc.in template for libpcre2-16.pc for pkg-config
libpcre2-32.pc.in template for libpcre2-32.pc for pkg-config
libpcre2posix.pc.in template for libpcre2posix.pc for pkg-config
ltmain.sh file used to build a libtool script
missing ) common stub for a few missing GNU programs while
) installing, generated by automake
mkinstalldirs script for making install directories
perltest.pl Perl test program
pcre2-config.in source of script which retains PCRE2 information
pcre2_jit_test.c test program for the JIT compiler
testdata/testinput* test data for main library tests
testdata/testoutput* expected test results
testdata/grep* input and output for pcre2grep tests
testdata/* other supporting test files
(D) Auxiliary files for cmake support
cmake/COPYING-CMAKE-SCRIPTS
cmake/FindPackageHandleStandardArgs.cmake
cmake/FindEditline.cmake
cmake/FindReadline.cmake
CMakeLists.txt
config-cmake.h.in
(E) Auxiliary files for VPASCAL FIXME FIXME
makevp.bat
makevp_c.txt
makevp_l.txt
pcre2gexp.pas
(F) Auxiliary files for building PCRE2 "by hand"
pcre2.h.generic ) a version of the public PCRE2 header file
) for use in non-"configure" environments
config.h.generic ) a version of config.h for use in non-"configure"
) environments
(F) Miscellaneous
RunTest.bat a script for running tests under Windows FIXME
Philip Hazel
Email local part: ph10
Email domain: cam.ac.uk
Last updated: 27 October 2014

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<html>
<head>
<title>pcre2-config specification</title>
</head>
<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
<h1>pcre2-config man page</h1>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>
<p>
This page is part of the PCRE2 HTML documentation. It was generated
automatically from the original man page. If there is any nonsense in it,
please consult the man page, in case the conversion went wrong.
<br>
<ul>
<li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
<li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
<li><a name="TOC3" href="#SEC3">OPTIONS</a>
<li><a name="TOC4" href="#SEC4">SEE ALSO</a>
<li><a name="TOC5" href="#SEC5">AUTHOR</a>
<li><a name="TOC6" href="#SEC6">REVISION</a>
</ul>
<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
<P>
<b>pcre2-config [--prefix] [--exec-prefix] [--version]</b>
<b> [--libs8] [--libs16] [--libs32] [--libs-posix]</b>
<b> [--cflags] [--cflags-posix]</b>
</P>
<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
<P>
<b>pcre2-config</b> returns the configuration of the installed PCRE2 libraries
and the options required to compile a program to use them. Some of the options
apply only to the 8-bit, or 16-bit, or 32-bit libraries, respectively, and are
not available for libraries that have not been built. If an unavailable option
is encountered, the "usage" information is output.
</P>
<br><a name="SEC3" href="#TOC1">OPTIONS</a><br>
<P>
<b>--prefix</b>
Writes the directory prefix used in the PCRE2 installation for architecture
independent files (<i>/usr</i> on many systems, <i>/usr/local</i> on some
systems) to the standard output.
</P>
<P>
<b>--exec-prefix</b>
Writes the directory prefix used in the PCRE2 installation for architecture
dependent files (normally the same as <b>--prefix</b>) to the standard output.
</P>
<P>
<b>--version</b>
Writes the version number of the installed PCRE2 libraries to the standard
output.
</P>
<P>
<b>--libs8</b>
Writes to the standard output the command line options required to link
with the 8-bit PCRE2 library (<b>-lpcre2-8</b> on many systems).
</P>
<P>
<b>--libs16</b>
Writes to the standard output the command line options required to link
with the 16-bit PCRE2 library (<b>-lpcre2-16</b> on many systems).
</P>
<P>
<b>--libs32</b>
Writes to the standard output the command line options required to link
with the 32-bit PCRE2 library (<b>-lpcre2-32</b> on many systems).
</P>
<P>
<b>--libs-posix</b>
Writes to the standard output the command line options required to link with
PCRE2's POSIX API wrapper library (<b>-lpcre2-posix</b> <b>-lpcre2-8</b> on many
systems).
</P>
<P>
<b>--cflags</b>
Writes to the standard output the command line options required to compile
files that use PCRE2 (this may include some <b>-I</b> options, but is blank on
many systems).
</P>
<P>
<b>--cflags-posix</b>
Writes to the standard output the command line options required to compile
files that use PCRE2's POSIX API wrapper library (this may include some
<b>-I</b> options, but is blank on many systems).
</P>
<br><a name="SEC4" href="#TOC1">SEE ALSO</a><br>
<P>
<b>pcre2(3)</b>
</P>
<br><a name="SEC5" href="#TOC1">AUTHOR</a><br>
<P>
This manual page was originally written by Mark Baker for the Debian GNU/Linux
system. It has been subsequently revised as a generic PCRE2 man page.
</P>
<br><a name="SEC6" href="#TOC1">REVISION</a><br>
<P>
Last updated: 28 September 2014
<br>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>

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<html>
<head>
<title>pcre2 specification</title>
</head>
<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
<h1>pcre2 man page</h1>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>
<p>
This page is part of the PCRE2 HTML documentation. It was generated
automatically from the original man page. If there is any nonsense in it,
please consult the man page, in case the conversion went wrong.
<br>
<ul>
<li><a name="TOC1" href="#SEC1">INTRODUCTION</a>
<li><a name="TOC2" href="#SEC2">SECURITY CONSIDERATIONS</a>
<li><a name="TOC3" href="#SEC3">USER DOCUMENTATION</a>
<li><a name="TOC4" href="#SEC4">AUTHOR</a>
<li><a name="TOC5" href="#SEC5">REVISION</a>
</ul>
<br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br>
<P>
PCRE2 is the name used for a revised API for the PCRE library, which is a set
of functions, written in C, that implement regular expression pattern matching
using the same syntax and semantics as Perl, with just a few differences. Some
features that appeared in Python and the original PCRE before they appeared in
Perl are also available using the Python syntax, there is some support for one
or two .NET and Oniguruma syntax items, and there are options for requesting
some minor changes that give better ECMAScript (aka JavaScript) compatibility.
</P>
<P>
The source code for PCRE2 can be compiled to support 8-bit, 16-bit, or 32-bit
code units, which means that up to three separate libraries may be installed.
The original work to extend PCRE to 16-bit and 32-bit code units was done by
Zoltan Herczeg and Christian Persch, respectively. In all three cases, strings
can be interpreted either as one character per code unit, or as UTF-encoded
Unicode, with support for Unicode general category properties. Unicode is
optional at build time, and must be enabled explicitly at run time. The version
of Unicode in use can be discovered by running
<pre>
pcre2test -C
</PRE>
</P>
<P>
The three libraries contain identical sets of functions, with names ending in
_8, _16, or _32, respectively (for example, <b>pcre2_compile_8()</b>). However,
by defining PCRE2_CODE_UNIT_WIDTH to be 8, 16, or 32, a program that uses just
one code unit width can be written using generic names such as
<b>pcre2_compile()</b>, and the documentation is written assuming that this is
the case.
</P>
<P>
In addition to the Perl-compatible matching function, PCRE2 contains an
alternative function that matches the same compiled patterns in a different
way. In certain circumstances, the alternative function has some advantages.
For a discussion of the two matching algorithms, see the
<a href="pcre2matching.html"><b>pcre2matching</b></a>
page.
</P>
<P>
Details of exactly which Perl regular expression features are and are not
supported by PCRE2 are given in separate documents. See the
<a href="pcre2pattern.html"><b>pcre2pattern</b></a>
and
<a href="pcre2compat.html"><b>pcre2compat</b></a>
pages. There is a syntax summary in the
<a href="pcre2syntax.html"><b>pcre2syntax</b></a>
page.
</P>
<P>
Some features of PCRE2 can be included, excluded, or changed when the library
is built. The
<a href="pcre2_config.html"><b>pcre2_config()</b></a>
function makes it possible for a client to discover which features are
available. The features themselves are described in the
<a href="pcre2build.html"><b>pcre2build</b></a>
page. Documentation about building PCRE2 for various operating systems can be
found in the
<a href="README.txt"><b>README</b></a>
and
<a href="NON-AUTOTOOLS-BUILD.txt"><b>NON-AUTOTOOLS_BUILD</b></a>
files in the source distribution.
</P>
<P>
The libraries contains a number of undocumented internal functions and data
tables that are used by more than one of the exported external functions, but
which are not intended for use by external callers. Their names all begin with
"_pcre2", which hopefully will not provoke any name clashes. In some
environments, it is possible to control which external symbols are exported
when a shared library is built, and in these cases the undocumented symbols are
not exported.
</P>
<br><a name="SEC2" href="#TOC1">SECURITY CONSIDERATIONS</a><br>
<P>
If you are using PCRE2 in a non-UTF application that permits users to supply
arbitrary patterns for compilation, you should be aware of a feature that
allows users to turn on UTF support from within a pattern, provided that PCRE2
was built with Unicode support. For example, an 8-bit pattern that begins with
"(*UTF)" turns on UTF-8 mode, which interprets patterns and subjects as strings
of UTF-8 code units instead of individual 8-bit characters. This causes both
the pattern and any data against which it is matched to be checked for UTF-8
validity. If the data string is very long, such a check might use sufficiently
many resources as to cause your application to lose performance.
</P>
<P>
One way of guarding against this possibility is to use the
<b>pcre2_pattern_info()</b> function to check the compiled pattern's options for
UTF. Alternatively, you can set the PCRE2_NEVER_UTF option at compile time.
This causes an compile time error if a pattern contains a UTF-setting sequence.
</P>
<P>
If your application is one that supports UTF, be aware that validity checking
can take time. If the same data string is to be matched many times, you can use
the PCRE2_NO_UTF_CHECK option for the second and subsequent matches to avoid
running redundant checks.
</P>
<P>
Another way that performance can be hit is by running a pattern that has a very
large search tree against a string that will never match. Nested unlimited
repeats in a pattern are a common example. PCRE2 provides some protection
against this: see the <b>pcre2_set_match_limit()</b> function in the
<a href="pcre2api.html"><b>pcre2api</b></a>
page.
</P>
<br><a name="SEC3" href="#TOC1">USER DOCUMENTATION</a><br>
<P>
The user documentation for PCRE2 comprises a number of different sections. In
the "man" format, each of these is a separate "man page". In the HTML format,
each is a separate page, linked from the index page. In the plain text format,
the descriptions of the <b>pcre2grep</b> and <b>pcre2test</b> programs are in
files called <b>pcre2grep.txt</b> and <b>pcre2test.txt</b>, respectively. The
remaining sections, except for the <b>pcre2demo</b> section (which is a program
listing), and the short pages for individual functions, are concatenated in
<b>pcre2.txt</b>, for ease of searching. The sections are as follows:
<pre>
pcre2 this document FIXME CHECK THIS LIST
pcre2-config show PCRE2 installation configuration information
pcre2api details of PCRE2's native C API
pcre2build building PCRE2
pcre2callout details of the callout feature
pcre2compat discussion of Perl compatibility
pcre2demo a demonstration C program that uses PCRE2
pcre2grep description of the <b>pcre2grep</b> command (8-bit only)
pcre2jit discussion of the just-in-time optimization support
pcre2limits details of size and other limits
pcre2matching discussion of the two matching algorithms
pcre2partial details of the partial matching facility
pcre2pattern syntax and semantics of supported regular expressions
pcre2perform discussion of performance issues
pcre2posix the POSIX-compatible C API for the 8-bit library
pcre2sample discussion of the pcre2demo program
pcre2stack discussion of stack usage
pcre2syntax quick syntax reference
pcre2test description of the <b>pcre2test</b> testing command
pcre2unicode discussion of Unicode and UTF support
</pre>
In the "man" and HTML formats, there is also a short page for each C library
function, listing its arguments and results.
</P>
<br><a name="SEC4" href="#TOC1">AUTHOR</a><br>
<P>
Philip Hazel
<br>
University Computing Service
<br>
Cambridge CB2 3QH, England.
<br>
</P>
<P>
Putting an actual email address here is a spam magnet. If you want to email me,
use my two initials, followed by the two digits 10, at the domain cam.ac.uk.
</P>
<br><a name="SEC5" href="#TOC1">REVISION</a><br>
<P>
Last updated: 28 September 2014
<br>
Copyright &copy; 1997-2014 University of Cambridge.
<br>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>

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<html>
<head>
<title>pcre2grep specification</title>
</head>
<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
<h1>pcre2grep man page</h1>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>
<p>
This page is part of the PCRE2 HTML documentation. It was generated
automatically from the original man page. If there is any nonsense in it,
please consult the man page, in case the conversion went wrong.
<br>
<ul>
<li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
<li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
<li><a name="TOC3" href="#SEC3">SUPPORT FOR COMPRESSED FILES</a>
<li><a name="TOC4" href="#SEC4">BINARY FILES</a>
<li><a name="TOC5" href="#SEC5">OPTIONS</a>
<li><a name="TOC6" href="#SEC6">ENVIRONMENT VARIABLES</a>
<li><a name="TOC7" href="#SEC7">NEWLINES</a>
<li><a name="TOC8" href="#SEC8">OPTIONS COMPATIBILITY</a>
<li><a name="TOC9" href="#SEC9">OPTIONS WITH DATA</a>
<li><a name="TOC10" href="#SEC10">MATCHING ERRORS</a>
<li><a name="TOC11" href="#SEC11">DIAGNOSTICS</a>
<li><a name="TOC12" href="#SEC12">SEE ALSO</a>
<li><a name="TOC13" href="#SEC13">AUTHOR</a>
<li><a name="TOC14" href="#SEC14">REVISION</a>
</ul>
<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
<P>
<b>pcre2grep [options] [long options] [pattern] [path1 path2 ...]</b>
</P>
<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
<P>
<b>pcre2grep</b> searches files for character patterns, in the same way as other
grep commands do, but it uses the PCRE2 regular expression library to support
patterns that are compatible with the regular expressions of Perl 5. See
<a href="pcre2syntax.html"><b>pcre2syntax</b>(3)</a>
for a quick-reference summary of pattern syntax, or
<a href="pcre2pattern.html"><b>pcre2pattern</b>(3)</a>
for a full description of the syntax and semantics of the regular expressions
that PCRE2 supports.
</P>
<P>
Patterns, whether supplied on the command line or in a separate file, are given
without delimiters. For example:
<pre>
pcre2grep Thursday /etc/motd
</pre>
If you attempt to use delimiters (for example, by surrounding a pattern with
slashes, as is common in Perl scripts), they are interpreted as part of the
pattern. Quotes can of course be used to delimit patterns on the command line
because they are interpreted by the shell, and indeed quotes are required if a
pattern contains white space or shell metacharacters.
</P>
<P>
The first argument that follows any option settings is treated as the single
pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present.
Conversely, when one or both of these options are used to specify patterns, all
arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an
argument pattern must be provided.
</P>
<P>
If no files are specified, <b>pcre2grep</b> reads the standard input. The
standard input can also be referenced by a name consisting of a single hyphen.
For example:
<pre>
pcre2grep some-pattern /file1 - /file3
</pre>
By default, each line that matches a pattern is copied to the standard
output, and if there is more than one file, the file name is output at the
start of each line, followed by a colon. However, there are options that can
change how <b>pcre2grep</b> behaves. In particular, the <b>-M</b> option makes it
possible to search for patterns that span line boundaries. What defines a line
boundary is controlled by the <b>-N</b> (<b>--newline</b>) option.
</P>
<P>
The amount of memory used for buffering files that are being scanned is
controlled by a parameter that can be set by the <b>--buffer-size</b> option.
The default value for this parameter is specified when <b>pcre2grep</b> is built,
with the default default being 20K. A block of memory three times this size is
used (to allow for buffering "before" and "after" lines). An error occurs if a
line overflows the buffer.
</P>
<P>
Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater.
BUFSIZ is defined in <b>&#60;stdio.h&#62;</b>. When there is more than one pattern
(specified by the use of <b>-e</b> and/or <b>-f</b>), each pattern is applied to
each line in the order in which they are defined, except that all the <b>-e</b>
patterns are tried before the <b>-f</b> patterns.
</P>
<P>
By default, as soon as one pattern matches a line, no further patterns are
considered. However, if <b>--colour</b> (or <b>--color</b>) is used to colour the
matching substrings, or if <b>--only-matching</b>, <b>--file-offsets</b>, or
<b>--line-offsets</b> is used to output only the part of the line that matched
(either shown literally, or as an offset), scanning resumes immediately
following the match, so that further matches on the same line can be found. If
there are multiple patterns, they are all tried on the remainder of the line,
but patterns that follow the one that matched are not tried on the earlier part
of the line.
</P>
<P>
This behaviour means that the order in which multiple patterns are specified
can affect the output when one of the above options is used. This is no longer
the same behaviour as GNU grep, which now manages to display earlier matches
for later patterns (as long as there is no overlap).
</P>
<P>
Patterns that can match an empty string are accepted, but empty string
matches are never recognized. An example is the pattern "(super)?(man)?", in
which all components are optional. This pattern finds all occurrences of both
"super" and "man"; the output differs from matching with "super|man" when only
the matching substrings are being shown.
</P>
<P>
If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set,
<b>pcre2grep</b> uses the value to set a locale when calling the PCRE2 library.
The <b>--locale</b> option can be used to override this.
</P>
<br><a name="SEC3" href="#TOC1">SUPPORT FOR COMPRESSED FILES</a><br>
<P>
It is possible to compile <b>pcre2grep</b> so that it uses <b>libz</b> or
<b>libbz2</b> to read files whose names end in <b>.gz</b> or <b>.bz2</b>,
respectively. You can find out whether your binary has support for one or both
of these file types by running it with the <b>--help</b> option. If the
appropriate support is not present, files are treated as plain text. The
standard input is always so treated.
</P>
<br><a name="SEC4" href="#TOC1">BINARY FILES</a><br>
<P>
By default, a file that contains a binary zero byte within the first 1024 bytes
is identified as a binary file, and is processed specially. (GNU grep also
identifies binary files in this manner.) See the <b>--binary-files</b> option
for a means of changing the way binary files are handled.
</P>
<br><a name="SEC5" href="#TOC1">OPTIONS</a><br>
<P>
The order in which some of the options appear can affect the output. For
example, both the <b>-h</b> and <b>-l</b> options affect the printing of file
names. Whichever comes later in the command line will be the one that takes
effect. Similarly, except where noted below, if an option is given twice, the
later setting is used. Numerical values for options may be followed by K or M,
to signify multiplication by 1024 or 1024*1024 respectively.
</P>
<P>
<b>--</b>
This terminates the list of options. It is useful if the next item on the
command line starts with a hyphen but is not an option. This allows for the
processing of patterns and filenames that start with hyphens.
</P>
<P>
<b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
Output <i>number</i> lines of context after each matching line. If filenames
and/or line numbers are being output, a hyphen separator is used instead of a
colon for the context lines. A line containing "--" is output between each
group of lines, unless they are in fact contiguous in the input file. The value
of <i>number</i> is expected to be relatively small. However, <b>pcre2grep</b>
guarantees to have up to 8K of following text available for context output.
</P>
<P>
<b>-a</b>, <b>--text</b>
Treat binary files as text. This is equivalent to
<b>--binary-files</b>=<i>text</i>.
</P>
<P>
<b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
Output <i>number</i> lines of context before each matching line. If filenames
and/or line numbers are being output, a hyphen separator is used instead of a
colon for the context lines. A line containing "--" is output between each
group of lines, unless they are in fact contiguous in the input file. The value
of <i>number</i> is expected to be relatively small. However, <b>pcre2grep</b>
guarantees to have up to 8K of preceding text available for context output.
</P>
<P>
<b>--binary-files=</b><i>word</i>
Specify how binary files are to be processed. If the word is "binary" (the
default), pattern matching is performed on binary files, but the only output is
"Binary file &#60;name&#62; matches" when a match succeeds. If the word is "text",
which is equivalent to the <b>-a</b> or <b>--text</b> option, binary files are
processed in the same way as any other file. In this case, when a match
succeeds, the output may be binary garbage, which can have nasty effects if
sent to a terminal. If the word is "without-match", which is equivalent to the
<b>-I</b> option, binary files are not processed at all; they are assumed not to
be of interest.
</P>
<P>
<b>--buffer-size=</b><i>number</i>
Set the parameter that controls how much memory is used for buffering files
that are being scanned.
</P>
<P>
<b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
Output <i>number</i> lines of context both before and after each matching line.
This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
</P>
<P>
<b>-c</b>, <b>--count</b>
Do not output individual lines from the files that are being scanned; instead
output the number of lines that would otherwise have been shown. If no lines
are selected, the number zero is output. If several files are are being
scanned, a count is output for each of them. However, if the
<b>--files-with-matches</b> option is also used, only those files whose counts
are greater than zero are listed. When <b>-c</b> is used, the <b>-A</b>,
<b>-B</b>, and <b>-C</b> options are ignored.
</P>
<P>
<b>--colour</b>, <b>--color</b>
If this option is given without any data, it is equivalent to "--colour=auto".
If data is required, it must be given in the same shell item, separated by an
equals sign.
</P>
<P>
<b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
This option specifies under what circumstances the parts of a line that matched
a pattern should be coloured in the output. By default, the output is not
coloured. The value (which is optional, see above) may be "never", "always", or
"auto". In the latter case, colouring happens only if the standard output is
connected to a terminal. More resources are used when colouring is enabled,
because <b>pcre2grep</b> has to search for all possible matches in a line, not
just one, in order to colour them all.
<br>
<br>
The colour that is used can be specified by setting the environment variable
PCRE2GREP_COLOUR or PCRE2GREP_COLOR. The value of this variable should be a
string of two numbers, separated by a semicolon. They are copied directly into
the control string for setting colour on a terminal, so it is your
responsibility to ensure that they make sense. If neither of the environment
variables is set, the default is "1;31", which gives red.
</P>
<P>
<b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
If an input path is not a regular file or a directory, "action" specifies how
it is to be processed. Valid values are "read" (the default) or "skip"
(silently skip the path).
</P>
<P>
<b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
If an input path is a directory, "action" specifies how it is to be processed.
Valid values are "read" (the default in non-Windows environments, for
compatibility with GNU grep), "recurse" (equivalent to the <b>-r</b> option), or
"skip" (silently skip the path, the default in Windows environments). In the
"read" case, directories are read as if they were ordinary files. In some
operating systems the effect of reading a directory like this is an immediate
end-of-file; in others it may provoke an error.
</P>
<P>
<b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i>
Specify a pattern to be matched. This option can be used multiple times in
order to specify several patterns. It can also be used as a way of specifying a
single pattern that starts with a hyphen. When <b>-e</b> is used, no argument
pattern is taken from the command line; all arguments are treated as file
names. There is no limit to the number of patterns. They are applied to each
line in the order in which they are defined until one matches.
<br>
<br>
If <b>-f</b> is used with <b>-e</b>, the command line patterns are matched first,
followed by the patterns from the file(s), independent of the order in which
these options are specified. Note that multiple use of <b>-e</b> is not the same
as a single pattern with alternatives. For example, X|Y finds the first
character in a line that is X or Y, whereas if the two patterns are given
separately, with X first, <b>pcre2grep</b> finds X if it is present, even if it
follows Y in the line. It finds Y only if there is no X in the line. This
matters only if you are using <b>-o</b> or <b>--colo(u)r</b> to show the part(s)
of the line that matched.
</P>
<P>
<b>--exclude</b>=<i>pattern</i>
Files (but not directories) whose names match the pattern are skipped without
being processed. This applies to all files, whether listed on the command line,
obtained from <b>--file-list</b>, or by scanning a directory. The pattern is a
PCRE2 regular expression, and is matched against the final component of the file
name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not
apply to this pattern. The option may be given any number of times in order to
specify multiple patterns. If a file name matches both an <b>--include</b>
and an <b>--exclude</b> pattern, it is excluded. There is no short form for this
option.
</P>
<P>
<b>--exclude-from=</b><i>filename</i>
Treat each non-empty line of the file as the data for an <b>--exclude</b>
option. What constitutes a newline when reading the file is the operating
system's default. The <b>--newline</b> option has no effect on this option. This
option may be given more than once in order to specify a number of files to
read.
</P>
<P>
<b>--exclude-dir</b>=<i>pattern</i>
Directories whose names match the pattern are skipped without being processed,
whatever the setting of the <b>--recursive</b> option. This applies to all
directories, whether listed on the command line, obtained from
<b>--file-list</b>, or by scanning a parent directory. The pattern is a PCRE2
regular expression, and is matched against the final component of the directory
name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not
apply to this pattern. The option may be given any number of times in order to
specify more than one pattern. If a directory matches both <b>--include-dir</b>
and <b>--exclude-dir</b>, it is excluded. There is no short form for this
option.
</P>
<P>
<b>-F</b>, <b>--fixed-strings</b>
Interpret each data-matching pattern as a list of fixed strings, separated by
newlines, instead of as a regular expression. What constitutes a newline for
this purpose is controlled by the <b>--newline</b> option. The <b>-w</b> (match
as a word) and <b>-x</b> (match whole line) options can be used with <b>-F</b>.
They apply to each of the fixed strings. A line is selected if any of the fixed
strings are found in it (subject to <b>-w</b> or <b>-x</b>, if present). This
option applies only to the patterns that are matched against the contents of
files; it does not apply to patterns specified by any of the <b>--include</b> or
<b>--exclude</b> options.
</P>
<P>
<b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
Read patterns from the file, one per line, and match them against
each line of input. What constitutes a newline when reading the file is the
operating system's default. The <b>--newline</b> option has no effect on this
option. Trailing white space is removed from each line, and blank lines are
ignored. An empty file contains no patterns and therefore matches nothing. See
also the comments about multiple patterns versus a single pattern with
alternatives in the description of <b>-e</b> above.
<br>
<br>
If this option is given more than once, all the specified files are
read. A data line is output if any of the patterns match it. A filename can
be given as "-" to refer to the standard input. When <b>-f</b> is used, patterns
specified on the command line using <b>-e</b> may also be present; they are
tested before the file's patterns. However, no other pattern is taken from the
command line; all arguments are treated as the names of paths to be searched.
</P>
<P>
<b>--file-list</b>=<i>filename</i>
Read a list of files and/or directories that are to be scanned from the given
file, one per line. Trailing white space is removed from each line, and blank
lines are ignored. These paths are processed before any that are listed on the
command line. The filename can be given as "-" to refer to the standard input.
If <b>--file</b> and <b>--file-list</b> are both specified as "-", patterns are
read first. This is useful only when the standard input is a terminal, from
which further lines (the list of files) can be read after an end-of-file
indication. If this option is given more than once, all the specified files are
read.
</P>
<P>
<b>--file-offsets</b>
Instead of showing lines or parts of lines that match, show each match as an
offset from the start of the file and a length, separated by a comma. In this
mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b>
options are ignored. If there is more than one match in a line, each of them is
shown separately. This option is mutually exclusive with <b>--line-offsets</b>
and <b>--only-matching</b>.
</P>
<P>
<b>-H</b>, <b>--with-filename</b>
Force the inclusion of the filename at the start of output lines when searching
a single file. By default, the filename is not shown in this case. For matching
lines, the filename is followed by a colon; for context lines, a hyphen
separator is used. If a line number is also being output, it follows the file
name.
</P>
<P>
<b>-h</b>, <b>--no-filename</b>
Suppress the output filenames when searching multiple files. By default,
filenames are shown when multiple files are searched. For matching lines, the
filename is followed by a colon; for context lines, a hyphen separator is used.
If a line number is also being output, it follows the file name.
</P>
<P>
<b>--help</b>
Output a help message, giving brief details of the command options and file
type support, and then exit. Anything else on the command line is
ignored.
</P>
<P>
<b>-I</b>
Treat binary files as never matching. This is equivalent to
<b>--binary-files</b>=<i>without-match</i>.
</P>
<P>
<b>-i</b>, <b>--ignore-case</b>
Ignore upper/lower case distinctions during comparisons.
</P>
<P>
<b>--include</b>=<i>pattern</i>
If any <b>--include</b> patterns are specified, the only files that are
processed are those that match one of the patterns (and do not match an
<b>--exclude</b> pattern). This option does not affect directories, but it
applies to all files, whether listed on the command line, obtained from
<b>--file-list</b>, or by scanning a directory. The pattern is a PCRE2 regular
expression, and is matched against the final component of the file name, not
the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not apply to
this pattern. The option may be given any number of times. If a file name
matches both an <b>--include</b> and an <b>--exclude</b> pattern, it is excluded.
There is no short form for this option.
</P>
<P>
<b>--include-from=</b><i>filename</i>
Treat each non-empty line of the file as the data for an <b>--include</b>
option. What constitutes a newline for this purpose is the operating system's
default. The <b>--newline</b> option has no effect on this option. This option
may be given any number of times; all the files are read.
</P>
<P>
<b>--include-dir</b>=<i>pattern</i>
If any <b>--include-dir</b> patterns are specified, the only directories that
are processed are those that match one of the patterns (and do not match an
<b>--exclude-dir</b> pattern). This applies to all directories, whether listed
on the command line, obtained from <b>--file-list</b>, or by scanning a parent
directory. The pattern is a PCRE2 regular expression, and is matched against the
final component of the directory name, not the entire path. The <b>-F</b>,
<b>-w</b>, and <b>-x</b> options do not apply to this pattern. The option may be
given any number of times. If a directory matches both <b>--include-dir</b> and
<b>--exclude-dir</b>, it is excluded. There is no short form for this option.
</P>
<P>
<b>-L</b>, <b>--files-without-match</b>
Instead of outputting lines from the files, just output the names of the files
that do not contain any lines that would have been output. Each file name is
output once, on a separate line.
</P>
<P>
<b>-l</b>, <b>--files-with-matches</b>
Instead of outputting lines from the files, just output the names of the files
containing lines that would have been output. Each file name is output
once, on a separate line. Searching normally stops as soon as a matching line
is found in a file. However, if the <b>-c</b> (count) option is also used,
matching continues in order to obtain the correct count, and those files that
have at least one match are listed along with their counts. Using this option
with <b>-c</b> is a way of suppressing the listing of files with no matches.
</P>
<P>
<b>--label</b>=<i>name</i>
This option supplies a name to be used for the standard input when file names
are being output. If not supplied, "(standard input)" is used. There is no
short form for this option.
</P>
<P>
<b>--line-buffered</b>
When this option is given, input is read and processed line by line, and the
output is flushed after each write. By default, input is read in large chunks,
unless <b>pcre2grep</b> can determine that it is reading from a terminal (which
is currently possible only in Unix-like environments). Output to terminal is
normally automatically flushed by the operating system. This option can be
useful when the input or output is attached to a pipe and you do not want
<b>pcre2grep</b> to buffer up large amounts of data. However, its use will affect
performance, and the <b>-M</b> (multiline) option ceases to work.
</P>
<P>
<b>--line-offsets</b>
Instead of showing lines or parts of lines that match, show each match as a
line number, the offset from the start of the line, and a length. The line
number is terminated by a colon (as usual; see the <b>-n</b> option), and the
offset and length are separated by a comma. In this mode, no context is shown.
That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is
more than one match in a line, each of them is shown separately. This option is
mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>.
</P>
<P>
<b>--locale</b>=<i>locale-name</i>
This option specifies a locale to be used for pattern matching. It overrides
the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
locale is specified, the PCRE2 library's default (usually the "C" locale) is
used. There is no short form for this option.
</P>
<P>
<b>--match-limit</b>=<i>number</i>
Processing some regular expression patterns can require a very large amount of
memory, leading in some cases to a program crash if not enough is available.
Other patterns may take a very long time to search for all possible matching
strings. The <b>pcre2_exec()</b> function that is called by <b>pcre2grep</b> to do
the matching has two parameters that can limit the resources that it uses.
<br>
<br>
The <b>--match-limit</b> option provides a means of limiting resource usage
when processing patterns that are not going to match, but which have a very
large number of possibilities in their search trees. The classic example is a
pattern that uses nested unlimited repeats. Internally, PCRE2 uses a function
called <b>match()</b> which it calls repeatedly (sometimes recursively). The
limit set by <b>--match-limit</b> is imposed on the number of times this
function is called during a match, which has the effect of limiting the amount
of backtracking that can take place.
<br>
<br>
The <b>--recursion-limit</b> option is similar to <b>--match-limit</b>, but
instead of limiting the total number of times that <b>match()</b> is called, it
limits the depth of recursive calls, which in turn limits the amount of memory
that can be used. The recursion depth is a smaller number than the total number
of calls, because not all calls to <b>match()</b> are recursive. This limit is
of use only if it is set smaller than <b>--match-limit</b>.
<br>
<br>
There are no short forms for these options. The default settings are specified
when the PCRE2 library is compiled, with the default default being 10 million.
</P>
<P>
<b>-M</b>, <b>--multiline</b>
Allow patterns to match more than one line. When this option is given, patterns
may usefully contain literal newline characters and internal occurrences of ^
and $ characters. The output for a successful match may consist of more than
one line, the last of which is the one in which the match ended. If the matched
string ends with a newline sequence the output ends at the end of that line.
<br>
<br>
When this option is set, the PCRE2 library is called in "multiline" mode.
There is a limit to the number of lines that can be matched, imposed by the way
that <b>pcre2grep</b> buffers the input file as it scans it. However,
<b>pcre2grep</b> ensures that at least 8K characters or the rest of the document
(whichever is the shorter) are available for forward matching, and similarly
the previous 8K characters (or all the previous characters, if fewer than 8K)
are guaranteed to be available for lookbehind assertions. This option does not
work when input is read line by line (see \fP--line-buffered\fP.)
</P>
<P>
<b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i>
The PCRE2 library supports five different conventions for indicating
the ends of lines. They are the single-character sequences CR (carriage return)
and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
which recognizes any of the preceding three types, and an "any" convention, in
which any Unicode line ending sequence is assumed to end a line. The Unicode
sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
(form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
PS (paragraph separator, U+2029).
<br>
<br>
When the PCRE2 library is built, a default line-ending sequence is specified.
This is normally the standard sequence for the operating system. Unless
otherwise specified by this option, <b>pcre2grep</b> uses the library's default.
The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
makes it possible to use <b>pcre2grep</b> to scan files that have come from other
environments without having to modify their line endings. If the data that is
being scanned does not agree with the convention set by this option,
<b>pcre2grep</b> may behave in strange ways. Note that this option does not
apply to files specified by the <b>-f</b>, <b>--exclude-from</b>, or
<b>--include-from</b> options, which are expected to use the operating system's
standard newline sequence.
</P>
<P>
<b>-n</b>, <b>--line-number</b>
Precede each output line by its line number in the file, followed by a colon
for matching lines or a hyphen for context lines. If the filename is also being
output, it precedes the line number. This option is forced if
<b>--line-offsets</b> is used.
</P>
<P>
<b>--no-jit</b>
If the PCRE2 library is built with support for just-in-time compiling (which
speeds up matching), <b>pcre2grep</b> automatically makes use of this, unless it
was explicitly disabled at build time. This option can be used to disable the
use of JIT at run time. It is provided for testing and working round problems.
It should never be needed in normal use.
</P>
<P>
<b>-o</b>, <b>--only-matching</b>
Show only the part of the line that matched a pattern instead of the whole
line. In this mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and
<b>-C</b> options are ignored. If there is more than one match in a line, each
of them is shown separately. If <b>-o</b> is combined with <b>-v</b> (invert the
sense of the match to find non-matching lines), no output is generated, but the
return code is set appropriately. If the matched portion of the line is empty,
nothing is output unless the file name or line number are being printed, in
which case they are shown on an otherwise empty line. This option is mutually
exclusive with <b>--file-offsets</b> and <b>--line-offsets</b>.
</P>
<P>
<b>-o</b><i>number</i>, <b>--only-matching</b>=<i>number</i>
Show only the part of the line that matched the capturing parentheses of the
given number. Up to 32 capturing parentheses are supported, and -o0 is
equivalent to <b>-o</b> without a number. Because these options can be given
without an argument (see above), if an argument is present, it must be given in
the same shell item, for example, -o3 or --only-matching=2. The comments given
for the non-argument case above also apply to this case. If the specified
capturing parentheses do not exist in the pattern, or were not set in the
match, nothing is output unless the file name or line number are being printed.
<br>
<br>
If this option is given multiple times, multiple substrings are output, in the
order the options are given. For example, -o3 -o1 -o3 causes the substrings
matched by capturing parentheses 3 and 1 and then 3 again to be output. By
default, there is no separator (but see the next option).
</P>
<P>
<b>--om-separator</b>=<i>text</i>
Specify a separating string for multiple occurrences of <b>-o</b>. The default
is an empty string. Separating strings are never coloured.
</P>
<P>
<b>-q</b>, <b>--quiet</b>
Work quietly, that is, display nothing except error messages. The exit
status indicates whether or not any matches were found.
</P>
<P>
<b>-r</b>, <b>--recursive</b>
If any given path is a directory, recursively scan the files it contains,
taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
directory is read as a normal file; in some operating systems this gives an
immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
option to "recurse".
</P>
<P>
<b>--recursion-limit</b>=<i>number</i>
See <b>--match-limit</b> above.
</P>
<P>
<b>-s</b>, <b>--no-messages</b>
Suppress error messages about non-existent or unreadable files. Such files are
quietly skipped. However, the return code is still 2, even if matches were
found in other files.
</P>
<P>
<b>-u</b>, <b>--utf-8</b>
Operate in UTF-8 mode. This option is available only if PCRE2 has been compiled
with UTF-8 support. All patterns (including those for any <b>--exclude</b> and
<b>--include</b> options) and all subject lines that are scanned must be valid
strings of UTF-8 characters.
</P>
<P>
<b>-V</b>, <b>--version</b>
Write the version numbers of <b>pcre2grep</b> and the PCRE2 library to the
standard output and then exit. Anything else on the command line is
ignored.
</P>
<P>
<b>-v</b>, <b>--invert-match</b>
Invert the sense of the match, so that lines which do <i>not</i> match any of
the patterns are the ones that are found.
</P>
<P>
<b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
Force the patterns to match only whole words. This is equivalent to having \b
at the start and end of the pattern. This option applies only to the patterns
that are matched against the contents of files; it does not apply to patterns
specified by any of the <b>--include</b> or <b>--exclude</b> options.
</P>
<P>
<b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b>
Force the patterns to be anchored (each must start matching at the beginning of
a line) and in addition, require them to match entire lines. This is equivalent
to having ^ and $ characters at the start and end of each alternative branch in
every pattern. This option applies only to the patterns that are matched
against the contents of files; it does not apply to patterns specified by any
of the <b>--include</b> or <b>--exclude</b> options.
</P>
<br><a name="SEC6" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
<P>
The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
order, for a locale. The first one that is set is used. This can be overridden
by the <b>--locale</b> option. If no locale is set, the PCRE2 library's default
(usually the "C" locale) is used.
</P>
<br><a name="SEC7" href="#TOC1">NEWLINES</a><br>
<P>
The <b>-N</b> (<b>--newline</b>) option allows <b>pcre2grep</b> to scan files with
different newline conventions from the default. Any parts of the input files
that are written to the standard output are copied identically, with whatever
newline sequences they have in the input. However, the setting of this option
does not affect the interpretation of files specified by the <b>-f</b>,
<b>--exclude-from</b>, or <b>--include-from</b> options, which are assumed to use
the operating system's standard newline sequence, nor does it affect the way in
which <b>pcre2grep</b> writes informational messages to the standard error and
output streams. For these it uses the string "\n" to indicate newlines,
relying on the C I/O library to convert this to an appropriate sequence.
</P>
<br><a name="SEC8" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
<P>
Many of the short and long forms of <b>pcre2grep</b>'s options are the same
as in the GNU <b>grep</b> program. Any long option of the form
<b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
(PCRE2 terminology). However, the <b>--file-list</b>, <b>--file-offsets</b>,
<b>--include-dir</b>, <b>--line-offsets</b>, <b>--locale</b>, <b>--match-limit</b>,
<b>-M</b>, <b>--multiline</b>, <b>-N</b>, <b>--newline</b>, <b>--om-separator</b>,
<b>--recursion-limit</b>, <b>-u</b>, and <b>--utf-8</b> options are specific to
<b>pcre2grep</b>, as is the use of the <b>--only-matching</b> option with a
capturing parentheses number.
</P>
<P>
Although most of the common options work the same way, a few are different in
<b>pcre2grep</b>. For example, the <b>--include</b> option's argument is a glob
for GNU <b>grep</b>, but a regular expression for <b>pcre2grep</b>. If both the
<b>-c</b> and <b>-l</b> options are given, GNU grep lists only file names,
without counts, but <b>pcre2grep</b> gives the counts.
</P>
<br><a name="SEC9" href="#TOC1">OPTIONS WITH DATA</a><br>
<P>
There are four different ways in which an option with data can be specified.
If a short form option is used, the data may follow immediately, or (with one
exception) in the next command line item. For example:
<pre>
-f/some/file
-f /some/file
</pre>
The exception is the <b>-o</b> option, which may appear with or without data.
Because of this, if data is present, it must follow immediately in the same
item, for example -o3.
</P>
<P>
If a long form option is used, the data may appear in the same command line
item, separated by an equals character, or (with two exceptions) it may appear
in the next command line item. For example:
<pre>
--file=/some/file
--file /some/file
</pre>
Note, however, that if you want to supply a file name beginning with ~ as data
in a shell command, and have the shell expand ~ to a home directory, you must
separate the file name from the option, because the shell does not treat ~
specially unless it is at the start of an item.
</P>
<P>
The exceptions to the above are the <b>--colour</b> (or <b>--color</b>) and
<b>--only-matching</b> options, for which the data is optional. If one of these
options does have data, it must be given in the first form, using an equals
character. Otherwise <b>pcre2grep</b> will assume that it has no data.
</P>
<br><a name="SEC10" href="#TOC1">MATCHING ERRORS</a><br>
<P>
It is possible to supply a regular expression that takes a very long time to
fail to match certain lines. Such patterns normally involve nested indefinite
repeats, for example: (a+)*\d when matched against a line of a's with no final
digit. The PCRE2 matching function has a resource limit that causes it to abort
in these circumstances. If this happens, <b>pcre2grep</b> outputs an error
message and the line that caused the problem to the standard error stream. If
there are more than 20 such errors, <b>pcre2grep</b> gives up.
</P>
<P>
The <b>--match-limit</b> option of <b>pcre2grep</b> can be used to set the overall
resource limit; there is a second option called <b>--recursion-limit</b> that
sets a limit on the amount of memory (usually stack) that is used (see the
discussion of these options above).
</P>
<br><a name="SEC11" href="#TOC1">DIAGNOSTICS</a><br>
<P>
Exit status is 0 if any matches were found, 1 if no matches were found, and 2
for syntax errors, overlong lines, non-existent or inaccessible files (even if
matches were found in other files) or too many matching errors. Using the
<b>-s</b> option to suppress error messages about inaccessible files does not
affect the return code.
</P>
<br><a name="SEC12" href="#TOC1">SEE ALSO</a><br>
<P>
<b>pcre2pattern</b>(3), <b>pcre2syntax</b>(3), <b>pcre2test</b>(1).
</P>
<br><a name="SEC13" href="#TOC1">AUTHOR</a><br>
<P>
Philip Hazel
<br>
University Computing Service
<br>
Cambridge CB2 3QH, England.
<br>
</P>
<br><a name="SEC14" href="#TOC1">REVISION</a><br>
<P>
Last updated: 28 September 2014
<br>
Copyright &copy; 1997-2014 University of Cambridge.
<br>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>

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.TH PCRE2-CONFIG 1 "28 September 2014" "PCRE2 10.00"
.SH NAME
pcre2-config - program to return PCRE2 configuration
.SH SYNOPSIS
.rs
.sp
.nf
.B pcre2-config [--prefix] [--exec-prefix] [--version]
.B " [--libs8] [--libs16] [--libs32] [--libs-posix]"
.B " [--cflags] [--cflags-posix]"
.fi
.
.
.SH DESCRIPTION
.rs
.sp
\fBpcre2-config\fP returns the configuration of the installed PCRE2 libraries
and the options required to compile a program to use them. Some of the options
apply only to the 8-bit, or 16-bit, or 32-bit libraries, respectively, and are
not available for libraries that have not been built. If an unavailable option
is encountered, the "usage" information is output.
.
.
.SH OPTIONS
.rs
.TP 10
\fB--prefix\fP
Writes the directory prefix used in the PCRE2 installation for architecture
independent files (\fI/usr\fP on many systems, \fI/usr/local\fP on some
systems) to the standard output.
.TP 10
\fB--exec-prefix\fP
Writes the directory prefix used in the PCRE2 installation for architecture
dependent files (normally the same as \fB--prefix\fP) to the standard output.
.TP 10
\fB--version\fP
Writes the version number of the installed PCRE2 libraries to the standard
output.
.TP 10
\fB--libs8\fP
Writes to the standard output the command line options required to link
with the 8-bit PCRE2 library (\fB-lpcre2-8\fP on many systems).
.TP 10
\fB--libs16\fP
Writes to the standard output the command line options required to link
with the 16-bit PCRE2 library (\fB-lpcre2-16\fP on many systems).
.TP 10
\fB--libs32\fP
Writes to the standard output the command line options required to link
with the 32-bit PCRE2 library (\fB-lpcre2-32\fP on many systems).
.TP 10
\fB--libs-posix\fP
Writes to the standard output the command line options required to link with
PCRE2's POSIX API wrapper library (\fB-lpcre2-posix\fP \fB-lpcre2-8\fP on many
systems).
.TP 10
\fB--cflags\fP
Writes to the standard output the command line options required to compile
files that use PCRE2 (this may include some \fB-I\fP options, but is blank on
many systems).
.TP 10
\fB--cflags-posix\fP
Writes to the standard output the command line options required to compile
files that use PCRE2's POSIX API wrapper library (this may include some
\fB-I\fP options, but is blank on many systems).
.
.
.SH "SEE ALSO"
.rs
.sp
\fBpcre2(3)\fP
.
.
.SH AUTHOR
.rs
.sp
This manual page was originally written by Mark Baker for the Debian GNU/Linux
system. It has been subsequently revised as a generic PCRE2 man page.
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 28 September 2014
.fi

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PCRE2-CONFIG(1) General Commands Manual PCRE2-CONFIG(1)
NAME
pcre2-config - program to return PCRE2 configuration
SYNOPSIS
pcre2-config [--prefix] [--exec-prefix] [--version]
[--libs8] [--libs16] [--libs32] [--libs-posix]
[--cflags] [--cflags-posix]
DESCRIPTION
pcre2-config returns the configuration of the installed PCRE2 libraries
and the options required to compile a program to use them. Some of the
options apply only to the 8-bit, or 16-bit, or 32-bit libraries,
respectively, and are not available for libraries that have not been
built. If an unavailable option is encountered, the "usage" information
is output.
OPTIONS
--prefix Writes the directory prefix used in the PCRE2 installation
for architecture independent files (/usr on many systems,
/usr/local on some systems) to the standard output.
--exec-prefix
Writes the directory prefix used in the PCRE2 installation
for architecture dependent files (normally the same as --pre-
fix) to the standard output.
--version Writes the version number of the installed PCRE2 libraries to
the standard output.
--libs8 Writes to the standard output the command line options
required to link with the 8-bit PCRE2 library (-lpcre2-8 on
many systems).
--libs16 Writes to the standard output the command line options
required to link with the 16-bit PCRE2 library (-lpcre2-16 on
many systems).
--libs32 Writes to the standard output the command line options
required to link with the 32-bit PCRE2 library (-lpcre2-32 on
many systems).
--libs-posix
Writes to the standard output the command line options
required to link with PCRE2's POSIX API wrapper library
(-lpcre2-posix -lpcre2-8 on many systems).
--cflags Writes to the standard output the command line options
required to compile files that use PCRE2 (this may include
some -I options, but is blank on many systems).
--cflags-posix
Writes to the standard output the command line options
required to compile files that use PCRE2's POSIX API wrapper
library (this may include some -I options, but is blank on
many systems).
SEE ALSO
pcre2(3)
AUTHOR
This manual page was originally written by Mark Baker for the Debian
GNU/Linux system. It has been subsequently revised as a generic PCRE2
man page.
REVISION
Last updated: 28 September 2014

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.TH PCRE2 3 "28 September 2014" "PCRE2 10.00"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH INTRODUCTION
.rs
.sp
PCRE2 is the name used for a revised API for the PCRE library, which is a set
of functions, written in C, that implement regular expression pattern matching
using the same syntax and semantics as Perl, with just a few differences. Some
features that appeared in Python and the original PCRE before they appeared in
Perl are also available using the Python syntax, there is some support for one
or two .NET and Oniguruma syntax items, and there are options for requesting
some minor changes that give better ECMAScript (aka JavaScript) compatibility.
.P
The source code for PCRE2 can be compiled to support 8-bit, 16-bit, or 32-bit
code units, which means that up to three separate libraries may be installed.
The original work to extend PCRE to 16-bit and 32-bit code units was done by
Zoltan Herczeg and Christian Persch, respectively. In all three cases, strings
can be interpreted either as one character per code unit, or as UTF-encoded
Unicode, with support for Unicode general category properties. Unicode is
optional at build time, and must be enabled explicitly at run time. The version
of Unicode in use can be discovered by running
.sp
pcre2test -C
.P
The three libraries contain identical sets of functions, with names ending in
_8, _16, or _32, respectively (for example, \fBpcre2_compile_8()\fP). However,
by defining PCRE2_CODE_UNIT_WIDTH to be 8, 16, or 32, a program that uses just
one code unit width can be written using generic names such as
\fBpcre2_compile()\fP, and the documentation is written assuming that this is
the case.
.P
In addition to the Perl-compatible matching function, PCRE2 contains an
alternative function that matches the same compiled patterns in a different
way. In certain circumstances, the alternative function has some advantages.
For a discussion of the two matching algorithms, see the
.\" HREF
\fBpcre2matching\fP
.\"
page.
.P
Details of exactly which Perl regular expression features are and are not
supported by PCRE2 are given in separate documents. See the
.\" HREF
\fBpcre2pattern\fP
.\"
and
.\" HREF
\fBpcre2compat\fP
.\"
pages. There is a syntax summary in the
.\" HREF
\fBpcre2syntax\fP
.\"
page.
.P
Some features of PCRE2 can be included, excluded, or changed when the library
is built. The
.\" HREF
\fBpcre2_config()\fP
.\"
function makes it possible for a client to discover which features are
available. The features themselves are described in the
.\" HREF
\fBpcre2build\fP
.\"
page. Documentation about building PCRE2 for various operating systems can be
found in the
.\" HTML <a href="README.txt">
.\" </a>
\fBREADME\fP
.\"
and
.\" HTML <a href="NON-AUTOTOOLS-BUILD.txt">
.\" </a>
\fBNON-AUTOTOOLS_BUILD\fP
.\"
files in the source distribution.
.P
The libraries contains a number of undocumented internal functions and data
tables that are used by more than one of the exported external functions, but
which are not intended for use by external callers. Their names all begin with
"_pcre2", which hopefully will not provoke any name clashes. In some
environments, it is possible to control which external symbols are exported
when a shared library is built, and in these cases the undocumented symbols are
not exported.
.
.
.SH "SECURITY CONSIDERATIONS"
.rs
.sp
If you are using PCRE2 in a non-UTF application that permits users to supply
arbitrary patterns for compilation, you should be aware of a feature that
allows users to turn on UTF support from within a pattern, provided that PCRE2
was built with Unicode support. For example, an 8-bit pattern that begins with
"(*UTF)" turns on UTF-8 mode, which interprets patterns and subjects as strings
of UTF-8 code units instead of individual 8-bit characters. This causes both
the pattern and any data against which it is matched to be checked for UTF-8
validity. If the data string is very long, such a check might use sufficiently
many resources as to cause your application to lose performance.
.P
One way of guarding against this possibility is to use the
\fBpcre2_pattern_info()\fP function to check the compiled pattern's options for
UTF. Alternatively, you can set the PCRE2_NEVER_UTF option at compile time.
This causes an compile time error if a pattern contains a UTF-setting sequence.
.P
If your application is one that supports UTF, be aware that validity checking
can take time. If the same data string is to be matched many times, you can use
the PCRE2_NO_UTF_CHECK option for the second and subsequent matches to avoid
running redundant checks.
.P
Another way that performance can be hit is by running a pattern that has a very
large search tree against a string that will never match. Nested unlimited
repeats in a pattern are a common example. PCRE2 provides some protection
against this: see the \fBpcre2_set_match_limit()\fP function in the
.\" HREF
\fBpcre2api\fP
.\"
page.
.
.
.SH "USER DOCUMENTATION"
.rs
.sp
The user documentation for PCRE2 comprises a number of different sections. In
the "man" format, each of these is a separate "man page". In the HTML format,
each is a separate page, linked from the index page. In the plain text format,
the descriptions of the \fBpcre2grep\fP and \fBpcre2test\fP programs are in
files called \fBpcre2grep.txt\fP and \fBpcre2test.txt\fP, respectively. The
remaining sections, except for the \fBpcre2demo\fP section (which is a program
listing), and the short pages for individual functions, are concatenated in
\fBpcre2.txt\fP, for ease of searching. The sections are as follows:
.sp
pcre2 this document FIXME CHECK THIS LIST
pcre2-config show PCRE2 installation configuration information
pcre2api details of PCRE2's native C API
pcre2build building PCRE2
pcre2callout details of the callout feature
pcre2compat discussion of Perl compatibility
pcre2demo a demonstration C program that uses PCRE2
pcre2grep description of the \fBpcre2grep\fP command (8-bit only)
pcre2jit discussion of the just-in-time optimization support
pcre2limits details of size and other limits
pcre2matching discussion of the two matching algorithms
pcre2partial details of the partial matching facility
.\" JOIN
pcre2pattern syntax and semantics of supported
regular expressions
pcre2perform discussion of performance issues
pcre2posix the POSIX-compatible C API for the 8-bit library
pcre2sample discussion of the pcre2demo program
pcre2stack discussion of stack usage
pcre2syntax quick syntax reference
pcre2test description of the \fBpcre2test\fP testing command
pcre2unicode discussion of Unicode and UTF support
.sp
In the "man" and HTML formats, there is also a short page for each C library
function, listing its arguments and results.
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.P
Putting an actual email address here is a spam magnet. If you want to email me,
use my two initials, followed by the two digits 10, at the domain cam.ac.uk.
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 28 September 2014
Copyright (c) 1997-2014 University of Cambridge.
.fi

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.TH PCRE2BUILD 3 "28 Sepember 2014" "PCRE2 10.00"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.
.
.SH "BUILDING PCRE2"
.rs
.sp
PCRE2 is distributed with a \fBconfigure\fP script that can be used to build
the library in Unix-like environments using the applications known as
Autotools. Also in the distribution are files to support building using
\fBCMake\fP instead of \fBconfigure\fP. The text file
.\" HTML <a href="README.txt">
.\" </a>
\fBREADME\fP
.\"
contains general information about building with Autotools (some of which is
repeated below), and also has some comments about building on various operating
systems. There is a lot more information about building PCRE2 without using
Autotools (including information about using \fBCMake\fP and building "by
hand") in the text file called
.\" HTML <a href="NON-AUTOTOOLS-BUILD.txt">
.\" </a>
\fBNON-AUTOTOOLS-BUILD\fP.
.\"
You should consult this file as well as the
.\" HTML <a href="README.txt">
.\" </a>
\fBREADME\fP
.\"
file if you are building in a non-Unix-like environment.
.
.
.SH "PCRE2 BUILD-TIME OPTIONS"
.rs
.sp
The rest of this document describes the optional features of PCRE2 that can be
selected when the library is compiled. It assumes use of the \fBconfigure\fP
script, where the optional features are selected or deselected by providing
options to \fBconfigure\fP before running the \fBmake\fP command. However, the
same options can be selected in both Unix-like and non-Unix-like environments
if you are using \fBCMake\fP instead of \fBconfigure\fP to build PCRE2.
.P
If you are not using Autotools or \fBCMake\fP, option selection can be done by
editing the \fBconfig.h\fP file, or by passing parameter settings to the
compiler, as described in
.\" HTML <a href="NON-AUTOTOOLS-BUILD.txt">
.\" </a>
\fBNON-AUTOTOOLS-BUILD\fP.
.\"
.P
The complete list of options for \fBconfigure\fP (which includes the standard
ones such as the selection of the installation directory) can be obtained by
running
.sp
./configure --help
.sp
The following sections include descriptions of options whose names begin with
--enable or --disable. These settings specify changes to the defaults for the
\fBconfigure\fP command. Because of the way that \fBconfigure\fP works,
--enable and --disable always come in pairs, so the complementary option always
exists as well, but as it specifies the default, it is not described.
.
.
.SH "BUILDING 8-BIT, 16-BIT AND 32-BIT LIBRARIES"
.rs
.sp
By default, a library called \fBlibpcre2-8\fP is built, containing functions
that take string arguments contained in vectors of bytes, interpreted either as
single-byte characters, or UTF-8 strings. You can also build two other
libraries, called \fBlibpcre2-16\fP and \fBlibpcre2-32\fP, which process
strings that are contained in vectors of 16-bit and 32-bit code units,
respectively. These can be interpreted either as single-unit characters or
UTF-16/UTF-32 strings. To build these additional libraries, add one or both of
the following to the \fBconfigure\fP command:
.sp
--enable-pcre16
--enable-pcre32
.sp
If you do not want the 8-bit library, add
.sp
--disable-pcre8
.sp
as well. At least one of the three libraries must be built. Note that the POSIX
wrapper is for the 8-bit library only, and that \fBpcre2grep\fP is an 8-bit
program. Neither of these are built if you select only the 16-bit or 32-bit
libraries.
.
.
.SH "BUILDING SHARED AND STATIC LIBRARIES"
.rs
.sp
The Autotools PCRE2 building process uses \fBlibtool\fP to build both shared
and static libraries by default. You can suppress one of these by adding one of
.sp
--disable-shared
--disable-static
.sp
to the \fBconfigure\fP command, as required.
.
.
.SH "Unicode and UTF SUPPORT"
.rs
.sp
To build PCRE2 with support for Unicode and UTF character strings, add
.sp
--enable-unicode
.sp
to the \fBconfigure\fP command. This setting applies to all three libraries,
adding support for UTF-8 to the 8-bit library, support for UTF-16 to the 16-bit
library, and support for UTF-32 to the to the 32-bit library.
It is not possible to build one library with
UTF support and another without in the same configuration.
.P
Of itself, this setting does not make PCRE2 treat strings as UTF-8, UTF-16 or
UTF-32. As well as compiling PCRE2 with this option, you also have have to set
the PCRE2_UTF option when you call \fBpcre2_compile()\fP to compile a pattern.
.P
If you set --enable-unicode when compiling in an EBCDIC environment, PCRE2
expects its input to be either ASCII or UTF-8 (depending on the run-time
option). It is not possible to support both EBCDIC and UTF-8 codes in the same
version of the library. Consequently, --enable-unicode and --enable-ebcdic are
mutually exclusive.
.P
UTF support allows the libraries to process character codepoints up to 0x10ffff
in the strings that they handle. It also provides support for accessing the
properties of such characters, using pattern escapes such as \eP, \ep, and \eX.
Only the general category properties such as \fILu\fP and \fINd\fP are
supported. Details are given in the
.\" HREF
\fBpcre2pattern\fP
.\"
documentation.
.
.
.SH "JUST-IN-TIME COMPILER SUPPORT"
.rs
.sp
Just-in-time compiler support is included in the build by specifying
.sp
--enable-jit
.sp
This support is available only for certain hardware architectures. If this
option is set for an unsupported architecture, a compile time error occurs.
See the
.\" HREF
\fBpcre2jit\fP
.\"
documentation for a discussion of JIT usage. When JIT support is enabled,
pcre2grep automatically makes use of it, unless you add
.sp
--disable-pcre2grep-jit
.sp
to the "configure" command.
.
.
.SH "CODE VALUE OF NEWLINE"
.rs
.sp
By default, PCRE2 interprets the linefeed (LF) character as indicating the end
of a line. This is the normal newline character on Unix-like systems. You can
compile PCRE2 to use carriage return (CR) instead, by adding
.sp
--enable-newline-is-cr
.sp
to the \fBconfigure\fP command. There is also a --enable-newline-is-lf option,
which explicitly specifies linefeed as the newline character.
.sp
Alternatively, you can specify that line endings are to be indicated by the two
character sequence CRLF. If you want this, add
.sp
--enable-newline-is-crlf
.sp
to the \fBconfigure\fP command. There is a fourth option, specified by
.sp
--enable-newline-is-anycrlf
.sp
which causes PCRE2 to recognize any of the three sequences CR, LF, or CRLF as
indicating a line ending. Finally, a fifth option, specified by
.sp
--enable-newline-is-any
.sp
causes PCRE2 to recognize any Unicode newline sequence.
.P
Whatever line ending convention is selected when PCRE2 is built can be
overridden when the library functions are called. At build time it is
conventional to use the standard for your operating system.
.
.
.SH "WHAT \eR MATCHES"
.rs
.sp
By default, the sequence \eR in a pattern matches any Unicode newline sequence,
whatever has been selected as the line ending sequence. If you specify
.sp
--enable-bsr-anycrlf
.sp
the default is changed so that \eR matches only CR, LF, or CRLF. Whatever is
selected when PCRE2 is built can be overridden when the library functions are
called.
.
.
.SH "HANDLING VERY LARGE PATTERNS"
.rs
.sp
Within a compiled pattern, offset values are used to point from one part to
another (for example, from an opening parenthesis to an alternation
metacharacter). By default, in the 8-bit and 16-bit libraries, two-byte values
are used for these offsets, leading to a maximum size for a compiled pattern of
around 64K. This is sufficient to handle all but the most gigantic patterns.
Nevertheless, some people do want to process truly enormous patterns, so it is
possible to compile PCRE2 to use three-byte or four-byte offsets by adding a
setting such as
.sp
--with-link-size=3
.sp
to the \fBconfigure\fP command. The value given must be 2, 3, or 4. For the
16-bit library, a value of 3 is rounded up to 4. In these libraries, using
longer offsets slows down the operation of PCRE2 because it has to load
additional data when handling them. For the 32-bit library the value is always
4 and cannot be overridden; the value of --with-link-size is ignored.
.
.
.SH "AVOIDING EXCESSIVE STACK USAGE"
.rs
.sp
When matching with the \fBpcre2_match()\fP function, PCRE2 implements
backtracking by making recursive calls to an internal function called
\fBmatch()\fP. In environments where the size of the stack is limited, this can
severely limit PCRE2's operation. (The Unix environment does not usually suffer
from this problem, but it may sometimes be necessary to increase the maximum
stack size. There is a discussion in the
.\" HREF
\fBpcre2stack\fP
.\"
documentation.) An alternative approach to recursion that uses memory from the
heap to remember data, instead of using recursive function calls, has been
implemented to work round the problem of limited stack size. If you want to
build a version of PCRE2 that works this way, add
.sp
--disable-stack-for-recursion
.sp
to the \fBconfigure\fP command. By default, the system functions \fBmalloc()\fP
and \fBfree()\fP are called to manage the heap memory that is required, but
custom memory management functions can be called instead. PCRE2 runs noticeably
more slowly when built in this way. This option affects only the
\fBpcre2_match()\fP function; it is not relevant for \fBpcre2_dfa_match()\fP.
.
.
.SH "LIMITING PCRE2 RESOURCE USAGE"
.rs
.sp
Internally, PCRE2 has a function called \fBmatch()\fP, which it calls
repeatedly (sometimes recursively) when matching a pattern with the
\fBpcre2_match()\fP function. By controlling the maximum number of times this
function may be called during a single matching operation, a limit can be
placed on the resources used by a single call to \fBpcre2_match()\fP. The limit
can be changed at run time, as described in the
.\" HREF
\fBpcre2api\fP
.\"
documentation. The default is 10 million, but this can be changed by adding a
setting such as
.sp
--with-match-limit=500000
.sp
to the \fBconfigure\fP command. This setting has no effect on the
\fBpcre2_dfa_match()\fP matching function.
.P
In some environments it is desirable to limit the depth of recursive calls of
\fBmatch()\fP more strictly than the total number of calls, in order to
restrict the maximum amount of stack (or heap, if --disable-stack-for-recursion
is specified) that is used. A second limit controls this; it defaults to the
value that is set for --with-match-limit, which imposes no additional
constraints. However, you can set a lower limit by adding, for example,
.sp
--with-match-limit-recursion=10000
.sp
to the \fBconfigure\fP command. This value can also be overridden at run time.
.
.
.SH "CREATING CHARACTER TABLES AT BUILD TIME"
.rs
.sp
PCRE2 uses fixed tables for processing characters whose code points are less
than 256. By default, PCRE2 is built with a set of tables that are distributed
in the file \fIsrc/pcre2_chartables.c.dist\fP. These tables are for ASCII codes
only. If you add
.sp
--enable-rebuild-chartables
.sp
to the \fBconfigure\fP command, the distributed tables are no longer used.
Instead, a program called \fBdftables\fP is compiled and run. This outputs the
source for new set of tables, created in the default locale of your C run-time
system. (This method of replacing the tables does not work if you are cross
compiling, because \fBdftables\fP is run on the local host. If you need to
create alternative tables when cross compiling, you will have to do so "by
hand".)
.
.
.SH "USING EBCDIC CODE"
.rs
.sp
PCRE2 assumes by default that it will run in an environment where the character
code is ASCII (or Unicode, which is a superset of ASCII). This is the case for
most computer operating systems. PCRE2 can, however, be compiled to run in an
EBCDIC environment by adding
.sp
--enable-ebcdic
.sp
to the \fBconfigure\fP command. This setting implies
--enable-rebuild-chartables. You should only use it if you know that you are in
an EBCDIC environment (for example, an IBM mainframe operating system). The
--enable-ebcdic option is incompatible with --enable-unicode.
.P
The EBCDIC character that corresponds to an ASCII LF is assumed to have the
value 0x15 by default. However, in some EBCDIC environments, 0x25 is used. In
such an environment you should use
.sp
--enable-ebcdic-nl25
.sp
as well as, or instead of, --enable-ebcdic. The EBCDIC character for CR has the
same value as in ASCII, namely, 0x0d. Whichever of 0x15 and 0x25 is \fInot\fP
chosen as LF is made to correspond to the Unicode NEL character (which, in
Unicode, is 0x85).
.P
The options that select newline behaviour, such as --enable-newline-is-cr,
and equivalent run-time options, refer to these character values in an EBCDIC
environment.
.
.
.SH "PCRE2GREP OPTIONS FOR COMPRESSED FILE SUPPORT"
.rs
.sp
By default, \fBpcre2grep\fP reads all files as plain text. You can build it so
that it recognizes files whose names end in \fB.gz\fP or \fB.bz2\fP, and reads
them with \fBlibz\fP or \fBlibbz2\fP, respectively, by adding one or both of
.sp
--enable-pcre2grep-libz
--enable-pcre2grep-libbz2
.sp
to the \fBconfigure\fP command. These options naturally require that the
relevant libraries are installed on your system. Configuration will fail if
they are not.
.
.
.SH "PCRE2GREP BUFFER SIZE"
.rs
.sp
\fBpcre2grep\fP uses an internal buffer to hold a "window" on the file it is
scanning, in order to be able to output "before" and "after" lines when it
finds a match. The size of the buffer is controlled by a parameter whose
default value is 20K. The buffer itself is three times this size, but because
of the way it is used for holding "before" lines, the longest line that is
guaranteed to be processable is the parameter size. You can change the default
parameter value by adding, for example,
.sp
--with-pcre2grep-bufsize=50K
.sp
to the \fBconfigure\fP command. The caller of \fPpcre2grep\fP can, however,
override this value by specifying a run-time option.
.
.
.SH "PCRE2TEST OPTION FOR LIBREADLINE SUPPORT"
.rs
.sp
If you add one of
.sp
--enable-pcre2test-libreadline
--enable-pcre2test-libedit
.sp
to the \fBconfigure\fP command, \fBpcre2test\fP is linked with the
\fBlibreadline\fP or\fBlibedit\fP library, respectively, and when its input is
from a terminal, it reads it using the \fBreadline()\fP function. This provides
line-editing and history facilities. Note that \fBlibreadline\fP is
GPL-licensed, so if you distribute a binary of \fBpcre2test\fP linked in this
way, there may be licensing issues. These can be avoided by linking with
\fBlibedit\fP (which has a BSD licence) instead.
.P
Setting this option causes the \fB-lreadline\fP option to be added to the
\fBpcre2test\fP build. In many operating environments with a sytem-installed
readline library this is sufficient. However, in some environments (e.g. if an
unmodified distribution version of readline is in use), some extra
configuration may be necessary. The INSTALL file for \fBlibreadline\fP says
this:
.sp
"Readline uses the termcap functions, but does not link with
the termcap or curses library itself, allowing applications
which link with readline the to choose an appropriate library."
.sp
If your environment has not been set up so that an appropriate library is
automatically included, you may need to add something like
.sp
LIBS="-ncurses"
.sp
immediately before the \fBconfigure\fP command.
.
.
.SH "DEBUGGING WITH VALGRIND SUPPORT"
.rs
.sp
By adding the
.sp
--enable-valgrind
.sp
option to to the \fBconfigure\fP command, PCRE2 will use valgrind annotations
to mark certain memory regions as unaddressable. This allows it to detect
invalid memory accesses, and is mostly useful for debugging PCRE2 itself.
.
.
.SH "CODE COVERAGE REPORTING"
.rs
.sp
If your C compiler is gcc, you can build a version of PCRE2 that can generate a
code coverage report for its test suite. To enable this, you must install
\fBlcov\fP version 1.6 or above. Then specify
.sp
--enable-coverage
.sp
to the \fBconfigure\fP command and build PCRE2 in the usual way.
.P
Note that using \fBccache\fP (a caching C compiler) is incompatible with code
coverage reporting. If you have configured \fBccache\fP to run automatically
on your system, you must set the environment variable
.sp
CCACHE_DISABLE=1
.sp
before running \fBmake\fP to build PCRE2, so that \fBccache\fP is not used.
.P
When --enable-coverage is used, the following addition targets are added to the
\fIMakefile\fP:
.sp
make coverage
.sp
This creates a fresh coverage report for the PCRE2 test suite. It is equivalent
to running "make coverage-reset", "make coverage-baseline", "make check", and
then "make coverage-report".
.sp
make coverage-reset
.sp
This zeroes the coverage counters, but does nothing else.
.sp
make coverage-baseline
.sp
This captures baseline coverage information.
.sp
make coverage-report
.sp
This creates the coverage report.
.sp
make coverage-clean-report
.sp
This removes the generated coverage report without cleaning the coverage data
itself.
.sp
make coverage-clean-data
.sp
This removes the captured coverage data without removing the coverage files
created at compile time (*.gcno).
.sp
make coverage-clean
.sp
This cleans all coverage data including the generated coverage report. For more
information about code coverage, see the \fBgcov\fP and \fBlcov\fP
documentation.
.
.
.SH "SEE ALSO"
.rs
.sp
\fBpcre2api\fP(3), \fBpcre2_config\fP(3).
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 28 September 2014
Copyright (c) 1997-2014 University of Cambridge.
.fi

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.TH PCRE2COMPAT 3 "28 September 2014" "PCRE2 10.0"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH "DIFFERENCES BETWEEN PCRE2 AND PERL"
.rs
.sp
This document describes the differences in the ways that PCRE2 and Perl handle
regular expressions. The differences described here are with respect to Perl
versions 5.10 and above.
.P
1. PCRE2 has only a subset of Perl's Unicode support. Details of what it does
have are given in the
.\" HREF
\fBpcre2unicode\fP
.\"
page.
.P
2. PCRE2 allows repeat quantifiers only on parenthesized assertions, but they
do not mean what you might think. For example, (?!a){3} does not assert that
the next three characters are not "a". It just asserts that the next character
is not "a" three times (in principle: PCRE2 optimizes this to run the assertion
just once). Perl allows repeat quantifiers on other assertions such as \eb, but
these do not seem to have any use.
.P
3. Capturing subpatterns that occur inside negative lookahead assertions are
counted, but their entries in the offsets vector are never set. Perl sometimes
(but not always) sets its numerical variables from inside negative assertions.
.P
4. The following Perl escape sequences are not supported: \el, \eu, \eL,
\eU, and \eN when followed by a character name or Unicode value. (\eN on its
own, matching a non-newline character, is supported.) In fact these are
implemented by Perl's general string-handling and are not part of its pattern
matching engine. If any of these are encountered by PCRE2, an error is
generated by default. However, if the PCRE2_ALT_BSUX option is set,
\eU and \eu are interpreted as ECMAScript interprets them.
.P
5. The Perl escape sequences \ep, \eP, and \eX are supported only if PCRE2 is
built with Unicode support. The properties that can be tested with \ep and \eP
are limited to the general category properties such as Lu and Nd, script names
such as Greek or Han, and the derived properties Any and L&. PCRE2 does support
the Cs (surrogate) property, which Perl does not; the Perl documentation says
"Because Perl hides the need for the user to understand the internal
representation of Unicode characters, there is no need to implement the
somewhat messy concept of surrogates."
.P
6. PCRE2 does support the \eQ...\eE escape for quoting substrings. Characters
in between are treated as literals. This is slightly different from Perl in
that $ and @ are also handled as literals inside the quotes. In Perl, they
cause variable interpolation (but of course PCRE2 does not have variables).
Note the following examples:
.sp
Pattern PCRE2 matches Perl matches
.sp
.\" JOIN
\eQabc$xyz\eE abc$xyz abc followed by the
contents of $xyz
\eQabc\e$xyz\eE abc\e$xyz abc\e$xyz
\eQabc\eE\e$\eQxyz\eE abc$xyz abc$xyz
.sp
The \eQ...\eE sequence is recognized both inside and outside character classes.
.P
7. Fairly obviously, PCRE2 does not support the (?{code}) and (??{code})
constructions. However, there is support for recursive patterns. This is not
available in Perl 5.8, but it is in Perl 5.10. Also, the PCRE2 "callout"
feature allows an external function to be called during pattern matching. See
the
.\" HREF
\fBpcre2callout\fP
.\"
documentation for details.
.P
8. Subpatterns that are called as subroutines (whether or not recursively) are
always treated as atomic groups in PCRE2. This is like Python, but unlike Perl.
Captured values that are set outside a subroutine call can be reference from
inside in PCRE2, but not in Perl. There is a discussion that explains these
differences in more detail in the
.\" HTML <a href="pcre2pattern.html#recursiondifference">
.\" </a>
section on recursion differences from Perl
.\"
in the
.\" HREF
\fBpcre2pattern\fP
.\"
page.
.P
9. If any of the backtracking control verbs are used in a subpattern that is
called as a subroutine (whether or not recursively), their effect is confined
to that subpattern; it does not extend to the surrounding pattern. This is not
always the case in Perl. In particular, if (*THEN) is present in a group that
is called as a subroutine, its action is limited to that group, even if the
group does not contain any | characters. Note that such subpatterns are
processed as anchored at the point where they are tested.
.P
10. If a pattern contains more than one backtracking control verb, the first
one that is backtracked onto acts. For example, in the pattern
A(*COMMIT)B(*PRUNE)C a failure in B triggers (*COMMIT), but a failure in C
triggers (*PRUNE). Perl's behaviour is more complex; in many cases it is the
same as PCRE2, but there are examples where it differs.
.P
11. Most backtracking verbs in assertions have their normal actions. They are
not confined to the assertion.
.P
12. There are some differences that are concerned with the settings of captured
strings when part of a pattern is repeated. For example, matching "aba" against
the pattern /^(a(b)?)+$/ in Perl leaves $2 unset, but in PCRE2 it is set to
"b".
.P
13. PCRE2's handling of duplicate subpattern numbers and duplicate subpattern
names is not as general as Perl's. This is a consequence of the fact the PCRE2
works internally just with numbers, using an external table to translate
between numbers and names. In particular, a pattern such as (?|(?<a>A)|(?<b)B),
where the two capturing parentheses have the same number but different names,
is not supported, and causes an error at compile time. If it were allowed, it
would not be possible to distinguish which parentheses matched, because both
names map to capturing subpattern number 1. To avoid this confusing situation,
an error is given at compile time.
.P
14. Perl recognizes comments in some places that PCRE2 does not, for example,
between the ( and ? at the start of a subpattern. If the /x modifier is set,
Perl allows white space between ( and ? (though current Perls warn that this is
deprecated) but PCRE2 never does, even if the PCRE2_EXTENDED option is set.
.P
15. Perl, when in warning mode, gives warnings for character classes such as
[A-\ed] or [a-[:digit:]]. It then treats the hyphens as literals. PCRE2 has no
warning features, so it gives an error in these cases because they are almost
certainly user mistakes.
.P
16. In PCRE2, the upper/lower case character properties Lu and Ll are not
affected when case-independent matching is specified. For example, \ep{Lu}
always matches an upper case letter. I think Perl has changed in this respect;
in the release at the time of writing (5.16), \ep{Lu} and \ep{Ll} match all
letters, regardless of case, when case independence is specified.
.P
17. PCRE2 provides some extensions to the Perl regular expression facilities.
Perl 5.10 includes new features that are not in earlier versions of Perl, some
of which (such as named parentheses) have been in PCRE2 for some time. This
list is with respect to Perl 5.10:
.sp
(a) Although lookbehind assertions in PCRE2 must match fixed length strings,
each alternative branch of a lookbehind assertion can match a different length
of string. Perl requires them all to have the same length.
.sp
(b) If PCRE2_DOLLAR_ENDONLY is set and PCRE2_MULTILINE is not set, the $
meta-character matches only at the very end of the string.
.sp
(c) A backslash followed by a letter with no special meaning is faulted. (Perl
can be made to issue a warning.)
.sp
(d) If PCRE2_UNGREEDY is set, the greediness of the repetition quantifiers is
inverted, that is, by default they are not greedy, but if followed by a
question mark they are.
.sp
(e) PCRE2_ANCHORED can be used at matching time to force a pattern to be tried
only at the first matching position in the subject string.
.sp
(f) The PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY, PCRE2_NOTEMPTY_ATSTART, and
PCRE2_NO_AUTO_CAPTURE options have no Perl equivalents.
.sp
(g) The \eR escape sequence can be restricted to match only CR, LF, or CRLF
by the PCRE2_BSR_ANYCRLF option.
.sp
(h) The callout facility is PCRE2-specific.
.sp
(i) The partial matching facility is PCRE2-specific.
.sp
(j) The alternative matching function (\fBpcre2_dfa_match()\fP matches in a
different way and is not Perl-compatible.
.sp
(k) PCRE2 recognizes some special sequences such as (*CR) at the start of
a pattern that set overall options that cannot be changed within the pattern.
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 28 September 2014
Copyright (c) 1997-2014 University of Cambridge.
.fi

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.TH PCRE2GREP 1 "28 September 2014" "PCRE2 10.00"
.SH NAME
pcre2grep - a grep with Perl-compatible regular expressions.
.SH SYNOPSIS
.B pcre2grep [options] [long options] [pattern] [path1 path2 ...]
.
.SH DESCRIPTION
.rs
.sp
\fBpcre2grep\fP searches files for character patterns, in the same way as other
grep commands do, but it uses the PCRE2 regular expression library to support
patterns that are compatible with the regular expressions of Perl 5. See
.\" HREF
\fBpcre2syntax\fP(3)
.\"
for a quick-reference summary of pattern syntax, or
.\" HREF
\fBpcre2pattern\fP(3)
.\"
for a full description of the syntax and semantics of the regular expressions
that PCRE2 supports.
.P
Patterns, whether supplied on the command line or in a separate file, are given
without delimiters. For example:
.sp
pcre2grep Thursday /etc/motd
.sp
If you attempt to use delimiters (for example, by surrounding a pattern with
slashes, as is common in Perl scripts), they are interpreted as part of the
pattern. Quotes can of course be used to delimit patterns on the command line
because they are interpreted by the shell, and indeed quotes are required if a
pattern contains white space or shell metacharacters.
.P
The first argument that follows any option settings is treated as the single
pattern to be matched when neither \fB-e\fP nor \fB-f\fP is present.
Conversely, when one or both of these options are used to specify patterns, all
arguments are treated as path names. At least one of \fB-e\fP, \fB-f\fP, or an
argument pattern must be provided.
.P
If no files are specified, \fBpcre2grep\fP reads the standard input. The
standard input can also be referenced by a name consisting of a single hyphen.
For example:
.sp
pcre2grep some-pattern /file1 - /file3
.sp
By default, each line that matches a pattern is copied to the standard
output, and if there is more than one file, the file name is output at the
start of each line, followed by a colon. However, there are options that can
change how \fBpcre2grep\fP behaves. In particular, the \fB-M\fP option makes it
possible to search for patterns that span line boundaries. What defines a line
boundary is controlled by the \fB-N\fP (\fB--newline\fP) option.
.P
The amount of memory used for buffering files that are being scanned is
controlled by a parameter that can be set by the \fB--buffer-size\fP option.
The default value for this parameter is specified when \fBpcre2grep\fP is built,
with the default default being 20K. A block of memory three times this size is
used (to allow for buffering "before" and "after" lines). An error occurs if a
line overflows the buffer.
.P
Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater.
BUFSIZ is defined in \fB<stdio.h>\fP. When there is more than one pattern
(specified by the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to
each line in the order in which they are defined, except that all the \fB-e\fP
patterns are tried before the \fB-f\fP patterns.
.P
By default, as soon as one pattern matches a line, no further patterns are
considered. However, if \fB--colour\fP (or \fB--color\fP) is used to colour the
matching substrings, or if \fB--only-matching\fP, \fB--file-offsets\fP, or
\fB--line-offsets\fP is used to output only the part of the line that matched
(either shown literally, or as an offset), scanning resumes immediately
following the match, so that further matches on the same line can be found. If
there are multiple patterns, they are all tried on the remainder of the line,
but patterns that follow the one that matched are not tried on the earlier part
of the line.
.P
This behaviour means that the order in which multiple patterns are specified
can affect the output when one of the above options is used. This is no longer
the same behaviour as GNU grep, which now manages to display earlier matches
for later patterns (as long as there is no overlap).
.P
Patterns that can match an empty string are accepted, but empty string
matches are never recognized. An example is the pattern "(super)?(man)?", in
which all components are optional. This pattern finds all occurrences of both
"super" and "man"; the output differs from matching with "super|man" when only
the matching substrings are being shown.
.P
If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set,
\fBpcre2grep\fP uses the value to set a locale when calling the PCRE2 library.
The \fB--locale\fP option can be used to override this.
.
.
.SH "SUPPORT FOR COMPRESSED FILES"
.rs
.sp
It is possible to compile \fBpcre2grep\fP so that it uses \fBlibz\fP or
\fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP,
respectively. You can find out whether your binary has support for one or both
of these file types by running it with the \fB--help\fP option. If the
appropriate support is not present, files are treated as plain text. The
standard input is always so treated.
.
.
.SH "BINARY FILES"
.rs
.sp
By default, a file that contains a binary zero byte within the first 1024 bytes
is identified as a binary file, and is processed specially. (GNU grep also
identifies binary files in this manner.) See the \fB--binary-files\fP option
for a means of changing the way binary files are handled.
.
.
.SH OPTIONS
.rs
.sp
The order in which some of the options appear can affect the output. For
example, both the \fB-h\fP and \fB-l\fP options affect the printing of file
names. Whichever comes later in the command line will be the one that takes
effect. Similarly, except where noted below, if an option is given twice, the
later setting is used. Numerical values for options may be followed by K or M,
to signify multiplication by 1024 or 1024*1024 respectively.
.TP 10
\fB--\fP
This terminates the list of options. It is useful if the next item on the
command line starts with a hyphen but is not an option. This allows for the
processing of patterns and filenames that start with hyphens.
.TP
\fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP
Output \fInumber\fP lines of context after each matching line. If filenames
and/or line numbers are being output, a hyphen separator is used instead of a
colon for the context lines. A line containing "--" is output between each
group of lines, unless they are in fact contiguous in the input file. The value
of \fInumber\fP is expected to be relatively small. However, \fBpcre2grep\fP
guarantees to have up to 8K of following text available for context output.
.TP
\fB-a\fP, \fB--text\fP
Treat binary files as text. This is equivalent to
\fB--binary-files\fP=\fItext\fP.
.TP
\fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP
Output \fInumber\fP lines of context before each matching line. If filenames
and/or line numbers are being output, a hyphen separator is used instead of a
colon for the context lines. A line containing "--" is output between each
group of lines, unless they are in fact contiguous in the input file. The value
of \fInumber\fP is expected to be relatively small. However, \fBpcre2grep\fP
guarantees to have up to 8K of preceding text available for context output.
.TP
\fB--binary-files=\fP\fIword\fP
Specify how binary files are to be processed. If the word is "binary" (the
default), pattern matching is performed on binary files, but the only output is
"Binary file <name> matches" when a match succeeds. If the word is "text",
which is equivalent to the \fB-a\fP or \fB--text\fP option, binary files are
processed in the same way as any other file. In this case, when a match
succeeds, the output may be binary garbage, which can have nasty effects if
sent to a terminal. If the word is "without-match", which is equivalent to the
\fB-I\fP option, binary files are not processed at all; they are assumed not to
be of interest.
.TP
\fB--buffer-size=\fP\fInumber\fP
Set the parameter that controls how much memory is used for buffering files
that are being scanned.
.TP
\fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP
Output \fInumber\fP lines of context both before and after each matching line.
This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
.TP
\fB-c\fP, \fB--count\fP
Do not output individual lines from the files that are being scanned; instead
output the number of lines that would otherwise have been shown. If no lines
are selected, the number zero is output. If several files are are being
scanned, a count is output for each of them. However, if the
\fB--files-with-matches\fP option is also used, only those files whose counts
are greater than zero are listed. When \fB-c\fP is used, the \fB-A\fP,
\fB-B\fP, and \fB-C\fP options are ignored.
.TP
\fB--colour\fP, \fB--color\fP
If this option is given without any data, it is equivalent to "--colour=auto".
If data is required, it must be given in the same shell item, separated by an
equals sign.
.TP
\fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP
This option specifies under what circumstances the parts of a line that matched
a pattern should be coloured in the output. By default, the output is not
coloured. The value (which is optional, see above) may be "never", "always", or
"auto". In the latter case, colouring happens only if the standard output is
connected to a terminal. More resources are used when colouring is enabled,
because \fBpcre2grep\fP has to search for all possible matches in a line, not
just one, in order to colour them all.
.sp
The colour that is used can be specified by setting the environment variable
PCRE2GREP_COLOUR or PCRE2GREP_COLOR. The value of this variable should be a
string of two numbers, separated by a semicolon. They are copied directly into
the control string for setting colour on a terminal, so it is your
responsibility to ensure that they make sense. If neither of the environment
variables is set, the default is "1;31", which gives red.
.TP
\fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP
If an input path is not a regular file or a directory, "action" specifies how
it is to be processed. Valid values are "read" (the default) or "skip"
(silently skip the path).
.TP
\fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP
If an input path is a directory, "action" specifies how it is to be processed.
Valid values are "read" (the default in non-Windows environments, for
compatibility with GNU grep), "recurse" (equivalent to the \fB-r\fP option), or
"skip" (silently skip the path, the default in Windows environments). In the
"read" case, directories are read as if they were ordinary files. In some
operating systems the effect of reading a directory like this is an immediate
end-of-file; in others it may provoke an error.
.TP
\fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP
Specify a pattern to be matched. This option can be used multiple times in
order to specify several patterns. It can also be used as a way of specifying a
single pattern that starts with a hyphen. When \fB-e\fP is used, no argument
pattern is taken from the command line; all arguments are treated as file
names. There is no limit to the number of patterns. They are applied to each
line in the order in which they are defined until one matches.
.sp
If \fB-f\fP is used with \fB-e\fP, the command line patterns are matched first,
followed by the patterns from the file(s), independent of the order in which
these options are specified. Note that multiple use of \fB-e\fP is not the same
as a single pattern with alternatives. For example, X|Y finds the first
character in a line that is X or Y, whereas if the two patterns are given
separately, with X first, \fBpcre2grep\fP finds X if it is present, even if it
follows Y in the line. It finds Y only if there is no X in the line. This
matters only if you are using \fB-o\fP or \fB--colo(u)r\fP to show the part(s)
of the line that matched.
.TP
\fB--exclude\fP=\fIpattern\fP
Files (but not directories) whose names match the pattern are skipped without
being processed. This applies to all files, whether listed on the command line,
obtained from \fB--file-list\fP, or by scanning a directory. The pattern is a
PCRE2 regular expression, and is matched against the final component of the file
name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not
apply to this pattern. The option may be given any number of times in order to
specify multiple patterns. If a file name matches both an \fB--include\fP
and an \fB--exclude\fP pattern, it is excluded. There is no short form for this
option.
.TP
\fB--exclude-from=\fP\fIfilename\fP
Treat each non-empty line of the file as the data for an \fB--exclude\fP
option. What constitutes a newline when reading the file is the operating
system's default. The \fB--newline\fP option has no effect on this option. This
option may be given more than once in order to specify a number of files to
read.
.TP
\fB--exclude-dir\fP=\fIpattern\fP
Directories whose names match the pattern are skipped without being processed,
whatever the setting of the \fB--recursive\fP option. This applies to all
directories, whether listed on the command line, obtained from
\fB--file-list\fP, or by scanning a parent directory. The pattern is a PCRE2
regular expression, and is matched against the final component of the directory
name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not
apply to this pattern. The option may be given any number of times in order to
specify more than one pattern. If a directory matches both \fB--include-dir\fP
and \fB--exclude-dir\fP, it is excluded. There is no short form for this
option.
.TP
\fB-F\fP, \fB--fixed-strings\fP
Interpret each data-matching pattern as a list of fixed strings, separated by
newlines, instead of as a regular expression. What constitutes a newline for
this purpose is controlled by the \fB--newline\fP option. The \fB-w\fP (match
as a word) and \fB-x\fP (match whole line) options can be used with \fB-F\fP.
They apply to each of the fixed strings. A line is selected if any of the fixed
strings are found in it (subject to \fB-w\fP or \fB-x\fP, if present). This
option applies only to the patterns that are matched against the contents of
files; it does not apply to patterns specified by any of the \fB--include\fP or
\fB--exclude\fP options.
.TP
\fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP
Read patterns from the file, one per line, and match them against
each line of input. What constitutes a newline when reading the file is the
operating system's default. The \fB--newline\fP option has no effect on this
option. Trailing white space is removed from each line, and blank lines are
ignored. An empty file contains no patterns and therefore matches nothing. See
also the comments about multiple patterns versus a single pattern with
alternatives in the description of \fB-e\fP above.
.sp
If this option is given more than once, all the specified files are
read. A data line is output if any of the patterns match it. A filename can
be given as "-" to refer to the standard input. When \fB-f\fP is used, patterns
specified on the command line using \fB-e\fP may also be present; they are
tested before the file's patterns. However, no other pattern is taken from the
command line; all arguments are treated as the names of paths to be searched.
.TP
\fB--file-list\fP=\fIfilename\fP
Read a list of files and/or directories that are to be scanned from the given
file, one per line. Trailing white space is removed from each line, and blank
lines are ignored. These paths are processed before any that are listed on the
command line. The filename can be given as "-" to refer to the standard input.
If \fB--file\fP and \fB--file-list\fP are both specified as "-", patterns are
read first. This is useful only when the standard input is a terminal, from
which further lines (the list of files) can be read after an end-of-file
indication. If this option is given more than once, all the specified files are
read.
.TP
\fB--file-offsets\fP
Instead of showing lines or parts of lines that match, show each match as an
offset from the start of the file and a length, separated by a comma. In this
mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP
options are ignored. If there is more than one match in a line, each of them is
shown separately. This option is mutually exclusive with \fB--line-offsets\fP
and \fB--only-matching\fP.
.TP
\fB-H\fP, \fB--with-filename\fP
Force the inclusion of the filename at the start of output lines when searching
a single file. By default, the filename is not shown in this case. For matching
lines, the filename is followed by a colon; for context lines, a hyphen
separator is used. If a line number is also being output, it follows the file
name.
.TP
\fB-h\fP, \fB--no-filename\fP
Suppress the output filenames when searching multiple files. By default,
filenames are shown when multiple files are searched. For matching lines, the
filename is followed by a colon; for context lines, a hyphen separator is used.
If a line number is also being output, it follows the file name.
.TP
\fB--help\fP
Output a help message, giving brief details of the command options and file
type support, and then exit. Anything else on the command line is
ignored.
.TP
\fB-I\fP
Treat binary files as never matching. This is equivalent to
\fB--binary-files\fP=\fIwithout-match\fP.
.TP
\fB-i\fP, \fB--ignore-case\fP
Ignore upper/lower case distinctions during comparisons.
.TP
\fB--include\fP=\fIpattern\fP
If any \fB--include\fP patterns are specified, the only files that are
processed are those that match one of the patterns (and do not match an
\fB--exclude\fP pattern). This option does not affect directories, but it
applies to all files, whether listed on the command line, obtained from
\fB--file-list\fP, or by scanning a directory. The pattern is a PCRE2 regular
expression, and is matched against the final component of the file name, not
the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not apply to
this pattern. The option may be given any number of times. If a file name
matches both an \fB--include\fP and an \fB--exclude\fP pattern, it is excluded.
There is no short form for this option.
.TP
\fB--include-from=\fP\fIfilename\fP
Treat each non-empty line of the file as the data for an \fB--include\fP
option. What constitutes a newline for this purpose is the operating system's
default. The \fB--newline\fP option has no effect on this option. This option
may be given any number of times; all the files are read.
.TP
\fB--include-dir\fP=\fIpattern\fP
If any \fB--include-dir\fP patterns are specified, the only directories that
are processed are those that match one of the patterns (and do not match an
\fB--exclude-dir\fP pattern). This applies to all directories, whether listed
on the command line, obtained from \fB--file-list\fP, or by scanning a parent
directory. The pattern is a PCRE2 regular expression, and is matched against the
final component of the directory name, not the entire path. The \fB-F\fP,
\fB-w\fP, and \fB-x\fP options do not apply to this pattern. The option may be
given any number of times. If a directory matches both \fB--include-dir\fP and
\fB--exclude-dir\fP, it is excluded. There is no short form for this option.
.TP
\fB-L\fP, \fB--files-without-match\fP
Instead of outputting lines from the files, just output the names of the files
that do not contain any lines that would have been output. Each file name is
output once, on a separate line.
.TP
\fB-l\fP, \fB--files-with-matches\fP
Instead of outputting lines from the files, just output the names of the files
containing lines that would have been output. Each file name is output
once, on a separate line. Searching normally stops as soon as a matching line
is found in a file. However, if the \fB-c\fP (count) option is also used,
matching continues in order to obtain the correct count, and those files that
have at least one match are listed along with their counts. Using this option
with \fB-c\fP is a way of suppressing the listing of files with no matches.
.TP
\fB--label\fP=\fIname\fP
This option supplies a name to be used for the standard input when file names
are being output. If not supplied, "(standard input)" is used. There is no
short form for this option.
.TP
\fB--line-buffered\fP
When this option is given, input is read and processed line by line, and the
output is flushed after each write. By default, input is read in large chunks,
unless \fBpcre2grep\fP can determine that it is reading from a terminal (which
is currently possible only in Unix-like environments). Output to terminal is
normally automatically flushed by the operating system. This option can be
useful when the input or output is attached to a pipe and you do not want
\fBpcre2grep\fP to buffer up large amounts of data. However, its use will affect
performance, and the \fB-M\fP (multiline) option ceases to work.
.TP
\fB--line-offsets\fP
Instead of showing lines or parts of lines that match, show each match as a
line number, the offset from the start of the line, and a length. The line
number is terminated by a colon (as usual; see the \fB-n\fP option), and the
offset and length are separated by a comma. In this mode, no context is shown.
That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is
more than one match in a line, each of them is shown separately. This option is
mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP.
.TP
\fB--locale\fP=\fIlocale-name\fP
This option specifies a locale to be used for pattern matching. It overrides
the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no
locale is specified, the PCRE2 library's default (usually the "C" locale) is
used. There is no short form for this option.
.TP
\fB--match-limit\fP=\fInumber\fP
Processing some regular expression patterns can require a very large amount of
memory, leading in some cases to a program crash if not enough is available.
Other patterns may take a very long time to search for all possible matching
strings. The \fBpcre2_exec()\fP function that is called by \fBpcre2grep\fP to do
the matching has two parameters that can limit the resources that it uses.
.sp
The \fB--match-limit\fP option provides a means of limiting resource usage
when processing patterns that are not going to match, but which have a very
large number of possibilities in their search trees. The classic example is a
pattern that uses nested unlimited repeats. Internally, PCRE2 uses a function
called \fBmatch()\fP which it calls repeatedly (sometimes recursively). The
limit set by \fB--match-limit\fP is imposed on the number of times this
function is called during a match, which has the effect of limiting the amount
of backtracking that can take place.
.sp
The \fB--recursion-limit\fP option is similar to \fB--match-limit\fP, but
instead of limiting the total number of times that \fBmatch()\fP is called, it
limits the depth of recursive calls, which in turn limits the amount of memory
that can be used. The recursion depth is a smaller number than the total number
of calls, because not all calls to \fBmatch()\fP are recursive. This limit is
of use only if it is set smaller than \fB--match-limit\fP.
.sp
There are no short forms for these options. The default settings are specified
when the PCRE2 library is compiled, with the default default being 10 million.
.TP
\fB-M\fP, \fB--multiline\fP
Allow patterns to match more than one line. When this option is given, patterns
may usefully contain literal newline characters and internal occurrences of ^
and $ characters. The output for a successful match may consist of more than
one line, the last of which is the one in which the match ended. If the matched
string ends with a newline sequence the output ends at the end of that line.
.sp
When this option is set, the PCRE2 library is called in "multiline" mode.
There is a limit to the number of lines that can be matched, imposed by the way
that \fBpcre2grep\fP buffers the input file as it scans it. However,
\fBpcre2grep\fP ensures that at least 8K characters or the rest of the document
(whichever is the shorter) are available for forward matching, and similarly
the previous 8K characters (or all the previous characters, if fewer than 8K)
are guaranteed to be available for lookbehind assertions. This option does not
work when input is read line by line (see \fP--line-buffered\fP.)
.TP
\fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP
The PCRE2 library supports five different conventions for indicating
the ends of lines. They are the single-character sequences CR (carriage return)
and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention,
which recognizes any of the preceding three types, and an "any" convention, in
which any Unicode line ending sequence is assumed to end a line. The Unicode
sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF
(form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and
PS (paragraph separator, U+2029).
.sp
When the PCRE2 library is built, a default line-ending sequence is specified.
This is normally the standard sequence for the operating system. Unless
otherwise specified by this option, \fBpcre2grep\fP uses the library's default.
The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This
makes it possible to use \fBpcre2grep\fP to scan files that have come from other
environments without having to modify their line endings. If the data that is
being scanned does not agree with the convention set by this option,
\fBpcre2grep\fP may behave in strange ways. Note that this option does not
apply to files specified by the \fB-f\fP, \fB--exclude-from\fP, or
\fB--include-from\fP options, which are expected to use the operating system's
standard newline sequence.
.TP
\fB-n\fP, \fB--line-number\fP
Precede each output line by its line number in the file, followed by a colon
for matching lines or a hyphen for context lines. If the filename is also being
output, it precedes the line number. This option is forced if
\fB--line-offsets\fP is used.
.TP
\fB--no-jit\fP
If the PCRE2 library is built with support for just-in-time compiling (which
speeds up matching), \fBpcre2grep\fP automatically makes use of this, unless it
was explicitly disabled at build time. This option can be used to disable the
use of JIT at run time. It is provided for testing and working round problems.
It should never be needed in normal use.
.TP
\fB-o\fP, \fB--only-matching\fP
Show only the part of the line that matched a pattern instead of the whole
line. In this mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and
\fB-C\fP options are ignored. If there is more than one match in a line, each
of them is shown separately. If \fB-o\fP is combined with \fB-v\fP (invert the
sense of the match to find non-matching lines), no output is generated, but the
return code is set appropriately. If the matched portion of the line is empty,
nothing is output unless the file name or line number are being printed, in
which case they are shown on an otherwise empty line. This option is mutually
exclusive with \fB--file-offsets\fP and \fB--line-offsets\fP.
.TP
\fB-o\fP\fInumber\fP, \fB--only-matching\fP=\fInumber\fP
Show only the part of the line that matched the capturing parentheses of the
given number. Up to 32 capturing parentheses are supported, and -o0 is
equivalent to \fB-o\fP without a number. Because these options can be given
without an argument (see above), if an argument is present, it must be given in
the same shell item, for example, -o3 or --only-matching=2. The comments given
for the non-argument case above also apply to this case. If the specified
capturing parentheses do not exist in the pattern, or were not set in the
match, nothing is output unless the file name or line number are being printed.
.sp
If this option is given multiple times, multiple substrings are output, in the
order the options are given. For example, -o3 -o1 -o3 causes the substrings
matched by capturing parentheses 3 and 1 and then 3 again to be output. By
default, there is no separator (but see the next option).
.TP
\fB--om-separator\fP=\fItext\fP
Specify a separating string for multiple occurrences of \fB-o\fP. The default
is an empty string. Separating strings are never coloured.
.TP
\fB-q\fP, \fB--quiet\fP
Work quietly, that is, display nothing except error messages. The exit
status indicates whether or not any matches were found.
.TP
\fB-r\fP, \fB--recursive\fP
If any given path is a directory, recursively scan the files it contains,
taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a
directory is read as a normal file; in some operating systems this gives an
immediate end-of-file. This option is a shorthand for setting the \fB-d\fP
option to "recurse".
.TP
\fB--recursion-limit\fP=\fInumber\fP
See \fB--match-limit\fP above.
.TP
\fB-s\fP, \fB--no-messages\fP
Suppress error messages about non-existent or unreadable files. Such files are
quietly skipped. However, the return code is still 2, even if matches were
found in other files.
.TP
\fB-u\fP, \fB--utf-8\fP
Operate in UTF-8 mode. This option is available only if PCRE2 has been compiled
with UTF-8 support. All patterns (including those for any \fB--exclude\fP and
\fB--include\fP options) and all subject lines that are scanned must be valid
strings of UTF-8 characters.
.TP
\fB-V\fP, \fB--version\fP
Write the version numbers of \fBpcre2grep\fP and the PCRE2 library to the
standard output and then exit. Anything else on the command line is
ignored.
.TP
\fB-v\fP, \fB--invert-match\fP
Invert the sense of the match, so that lines which do \fInot\fP match any of
the patterns are the ones that are found.
.TP
\fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP
Force the patterns to match only whole words. This is equivalent to having \eb
at the start and end of the pattern. This option applies only to the patterns
that are matched against the contents of files; it does not apply to patterns
specified by any of the \fB--include\fP or \fB--exclude\fP options.
.TP
\fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP
Force the patterns to be anchored (each must start matching at the beginning of
a line) and in addition, require them to match entire lines. This is equivalent
to having ^ and $ characters at the start and end of each alternative branch in
every pattern. This option applies only to the patterns that are matched
against the contents of files; it does not apply to patterns specified by any
of the \fB--include\fP or \fB--exclude\fP options.
.
.
.SH "ENVIRONMENT VARIABLES"
.rs
.sp
The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that
order, for a locale. The first one that is set is used. This can be overridden
by the \fB--locale\fP option. If no locale is set, the PCRE2 library's default
(usually the "C" locale) is used.
.
.
.SH "NEWLINES"
.rs
.sp
The \fB-N\fP (\fB--newline\fP) option allows \fBpcre2grep\fP to scan files with
different newline conventions from the default. Any parts of the input files
that are written to the standard output are copied identically, with whatever
newline sequences they have in the input. However, the setting of this option
does not affect the interpretation of files specified by the \fB-f\fP,
\fB--exclude-from\fP, or \fB--include-from\fP options, which are assumed to use
the operating system's standard newline sequence, nor does it affect the way in
which \fBpcre2grep\fP writes informational messages to the standard error and
output streams. For these it uses the string "\en" to indicate newlines,
relying on the C I/O library to convert this to an appropriate sequence.
.
.
.SH "OPTIONS COMPATIBILITY"
.rs
.sp
Many of the short and long forms of \fBpcre2grep\fP's options are the same
as in the GNU \fBgrep\fP program. Any long option of the form
\fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP
(PCRE2 terminology). However, the \fB--file-list\fP, \fB--file-offsets\fP,
\fB--include-dir\fP, \fB--line-offsets\fP, \fB--locale\fP, \fB--match-limit\fP,
\fB-M\fP, \fB--multiline\fP, \fB-N\fP, \fB--newline\fP, \fB--om-separator\fP,
\fB--recursion-limit\fP, \fB-u\fP, and \fB--utf-8\fP options are specific to
\fBpcre2grep\fP, as is the use of the \fB--only-matching\fP option with a
capturing parentheses number.
.P
Although most of the common options work the same way, a few are different in
\fBpcre2grep\fP. For example, the \fB--include\fP option's argument is a glob
for GNU \fBgrep\fP, but a regular expression for \fBpcre2grep\fP. If both the
\fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names,
without counts, but \fBpcre2grep\fP gives the counts.
.
.
.SH "OPTIONS WITH DATA"
.rs
.sp
There are four different ways in which an option with data can be specified.
If a short form option is used, the data may follow immediately, or (with one
exception) in the next command line item. For example:
.sp
-f/some/file
-f /some/file
.sp
The exception is the \fB-o\fP option, which may appear with or without data.
Because of this, if data is present, it must follow immediately in the same
item, for example -o3.
.P
If a long form option is used, the data may appear in the same command line
item, separated by an equals character, or (with two exceptions) it may appear
in the next command line item. For example:
.sp
--file=/some/file
--file /some/file
.sp
Note, however, that if you want to supply a file name beginning with ~ as data
in a shell command, and have the shell expand ~ to a home directory, you must
separate the file name from the option, because the shell does not treat ~
specially unless it is at the start of an item.
.P
The exceptions to the above are the \fB--colour\fP (or \fB--color\fP) and
\fB--only-matching\fP options, for which the data is optional. If one of these
options does have data, it must be given in the first form, using an equals
character. Otherwise \fBpcre2grep\fP will assume that it has no data.
.
.
.SH "MATCHING ERRORS"
.rs
.sp
It is possible to supply a regular expression that takes a very long time to
fail to match certain lines. Such patterns normally involve nested indefinite
repeats, for example: (a+)*\ed when matched against a line of a's with no final
digit. The PCRE2 matching function has a resource limit that causes it to abort
in these circumstances. If this happens, \fBpcre2grep\fP outputs an error
message and the line that caused the problem to the standard error stream. If
there are more than 20 such errors, \fBpcre2grep\fP gives up.
.P
The \fB--match-limit\fP option of \fBpcre2grep\fP can be used to set the overall
resource limit; there is a second option called \fB--recursion-limit\fP that
sets a limit on the amount of memory (usually stack) that is used (see the
discussion of these options above).
.
.
.SH DIAGNOSTICS
.rs
.sp
Exit status is 0 if any matches were found, 1 if no matches were found, and 2
for syntax errors, overlong lines, non-existent or inaccessible files (even if
matches were found in other files) or too many matching errors. Using the
\fB-s\fP option to suppress error messages about inaccessible files does not
affect the return code.
.
.
.SH "SEE ALSO"
.rs
.sp
\fBpcre2pattern\fP(3), \fBpcre2syntax\fP(3), \fBpcre2test\fP(1).
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 28 September 2014
Copyright (c) 1997-2014 University of Cambridge.
.fi

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PCRE2GREP(1) General Commands Manual PCRE2GREP(1)
NAME
pcre2grep - a grep with Perl-compatible regular expressions.
SYNOPSIS
pcre2grep [options] [long options] [pattern] [path1 path2 ...]
DESCRIPTION
pcre2grep searches files for character patterns, in the same way as
other grep commands do, but it uses the PCRE2 regular expression
library to support patterns that are compatible with the regular
expressions of Perl 5. See pcre2syntax(3) for a quick-reference summary
of pattern syntax, or pcre2pattern(3) for a full description of the
syntax and semantics of the regular expressions that PCRE2 supports.
Patterns, whether supplied on the command line or in a separate file,
are given without delimiters. For example:
pcre2grep Thursday /etc/motd
If you attempt to use delimiters (for example, by surrounding a pattern
with slashes, as is common in Perl scripts), they are interpreted as
part of the pattern. Quotes can of course be used to delimit patterns
on the command line because they are interpreted by the shell, and
indeed quotes are required if a pattern contains white space or shell
metacharacters.
The first argument that follows any option settings is treated as the
single pattern to be matched when neither -e nor -f is present. Con-
versely, when one or both of these options are used to specify pat-
terns, all arguments are treated as path names. At least one of -e, -f,
or an argument pattern must be provided.
If no files are specified, pcre2grep reads the standard input. The
standard input can also be referenced by a name consisting of a single
hyphen. For example:
pcre2grep some-pattern /file1 - /file3
By default, each line that matches a pattern is copied to the standard
output, and if there is more than one file, the file name is output at
the start of each line, followed by a colon. However, there are options
that can change how pcre2grep behaves. In particular, the -M option
makes it possible to search for patterns that span line boundaries.
What defines a line boundary is controlled by the -N (--newline)
option.
The amount of memory used for buffering files that are being scanned is
controlled by a parameter that can be set by the --buffer-size option.
The default value for this parameter is specified when pcre2grep is
built, with the default default being 20K. A block of memory three
times this size is used (to allow for buffering "before" and "after"
lines). An error occurs if a line overflows the buffer.
Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the
greater. BUFSIZ is defined in <stdio.h>. When there is more than one
pattern (specified by the use of -e and/or -f), each pattern is applied
to each line in the order in which they are defined, except that all
the -e patterns are tried before the -f patterns.
By default, as soon as one pattern matches a line, no further patterns
are considered. However, if --colour (or --color) is used to colour the
matching substrings, or if --only-matching, --file-offsets, or --line-
offsets is used to output only the part of the line that matched
(either shown literally, or as an offset), scanning resumes immediately
following the match, so that further matches on the same line can be
found. If there are multiple patterns, they are all tried on the
remainder of the line, but patterns that follow the one that matched
are not tried on the earlier part of the line.
This behaviour means that the order in which multiple patterns are
specified can affect the output when one of the above options is used.
This is no longer the same behaviour as GNU grep, which now manages to
display earlier matches for later patterns (as long as there is no
overlap).
Patterns that can match an empty string are accepted, but empty string
matches are never recognized. An example is the pattern
"(super)?(man)?", in which all components are optional. This pattern
finds all occurrences of both "super" and "man"; the output differs
from matching with "super|man" when only the matching substrings are
being shown.
If the LC_ALL or LC_CTYPE environment variable is set, pcre2grep uses
the value to set a locale when calling the PCRE2 library. The --locale
option can be used to override this.
SUPPORT FOR COMPRESSED FILES
It is possible to compile pcre2grep so that it uses libz or libbz2 to
read files whose names end in .gz or .bz2, respectively. You can find
out whether your binary has support for one or both of these file types
by running it with the --help option. If the appropriate support is not
present, files are treated as plain text. The standard input is always
so treated.
BINARY FILES
By default, a file that contains a binary zero byte within the first
1024 bytes is identified as a binary file, and is processed specially.
(GNU grep also identifies binary files in this manner.) See the
--binary-files option for a means of changing the way binary files are
handled.
OPTIONS
The order in which some of the options appear can affect the output.
For example, both the -h and -l options affect the printing of file
names. Whichever comes later in the command line will be the one that
takes effect. Similarly, except where noted below, if an option is
given twice, the later setting is used. Numerical values for options
may be followed by K or M, to signify multiplication by 1024 or
1024*1024 respectively.
-- This terminates the list of options. It is useful if the next
item on the command line starts with a hyphen but is not an
option. This allows for the processing of patterns and file-
names that start with hyphens.
-A number, --after-context=number
Output number lines of context after each matching line. If
filenames and/or line numbers are being output, a hyphen sep-
arator is used instead of a colon for the context lines. A
line containing "--" is output between each group of lines,
unless they are in fact contiguous in the input file. The
value of number is expected to be relatively small. However,
pcre2grep guarantees to have up to 8K of following text
available for context output.
-a, --text
Treat binary files as text. This is equivalent to --binary-
files=text.
-B number, --before-context=number
Output number lines of context before each matching line. If
filenames and/or line numbers are being output, a hyphen sep-
arator is used instead of a colon for the context lines. A
line containing "--" is output between each group of lines,
unless they are in fact contiguous in the input file. The
value of number is expected to be relatively small. However,
pcre2grep guarantees to have up to 8K of preceding text
available for context output.
--binary-files=word
Specify how binary files are to be processed. If the word is
"binary" (the default), pattern matching is performed on
binary files, but the only output is "Binary file <name>
matches" when a match succeeds. If the word is "text", which
is equivalent to the -a or --text option, binary files are
processed in the same way as any other file. In this case,
when a match succeeds, the output may be binary garbage,
which can have nasty effects if sent to a terminal. If the
word is "without-match", which is equivalent to the -I
option, binary files are not processed at all; they are
assumed not to be of interest.
--buffer-size=number
Set the parameter that controls how much memory is used for
buffering files that are being scanned.
-C number, --context=number
Output number lines of context both before and after each
matching line. This is equivalent to setting both -A and -B
to the same value.
-c, --count
Do not output individual lines from the files that are being
scanned; instead output the number of lines that would other-
wise have been shown. If no lines are selected, the number
zero is output. If several files are are being scanned, a
count is output for each of them. However, if the --files-
with-matches option is also used, only those files whose
counts are greater than zero are listed. When -c is used, the
-A, -B, and -C options are ignored.
--colour, --color
If this option is given without any data, it is equivalent to
"--colour=auto". If data is required, it must be given in
the same shell item, separated by an equals sign.
--colour=value, --color=value
This option specifies under what circumstances the parts of a
line that matched a pattern should be coloured in the output.
By default, the output is not coloured. The value (which is
optional, see above) may be "never", "always", or "auto". In
the latter case, colouring happens only if the standard out-
put is connected to a terminal. More resources are used when
colouring is enabled, because pcre2grep has to search for all
possible matches in a line, not just one, in order to colour
them all.
The colour that is used can be specified by setting the envi-
ronment variable PCRE2GREP_COLOUR or PCRE2GREP_COLOR. The
value of this variable should be a string of two numbers,
separated by a semicolon. They are copied directly into the
control string for setting colour on a terminal, so it is
your responsibility to ensure that they make sense. If nei-
ther of the environment variables is set, the default is
"1;31", which gives red.
-D action, --devices=action
If an input path is not a regular file or a directory,
"action" specifies how it is to be processed. Valid values
are "read" (the default) or "skip" (silently skip the path).
-d action, --directories=action
If an input path is a directory, "action" specifies how it is
to be processed. Valid values are "read" (the default in
non-Windows environments, for compatibility with GNU grep),
"recurse" (equivalent to the -r option), or "skip" (silently
skip the path, the default in Windows environments). In the
"read" case, directories are read as if they were ordinary
files. In some operating systems the effect of reading a
directory like this is an immediate end-of-file; in others it
may provoke an error.
-e pattern, --regex=pattern, --regexp=pattern
Specify a pattern to be matched. This option can be used mul-
tiple times in order to specify several patterns. It can also
be used as a way of specifying a single pattern that starts
with a hyphen. When -e is used, no argument pattern is taken
from the command line; all arguments are treated as file
names. There is no limit to the number of patterns. They are
applied to each line in the order in which they are defined
until one matches.
If -f is used with -e, the command line patterns are matched
first, followed by the patterns from the file(s), independent
of the order in which these options are specified. Note that
multiple use of -e is not the same as a single pattern with
alternatives. For example, X|Y finds the first character in a
line that is X or Y, whereas if the two patterns are given
separately, with X first, pcre2grep finds X if it is present,
even if it follows Y in the line. It finds Y only if there is
no X in the line. This matters only if you are using -o or
--colo(u)r to show the part(s) of the line that matched.
--exclude=pattern
Files (but not directories) whose names match the pattern are
skipped without being processed. This applies to all files,
whether listed on the command line, obtained from --file-
list, or by scanning a directory. The pattern is a PCRE2 reg-
ular expression, and is matched against the final component
of the file name, not the entire path. The -F, -w, and -x
options do not apply to this pattern. The option may be given
any number of times in order to specify multiple patterns. If
a file name matches both an --include and an --exclude pat-
tern, it is excluded. There is no short form for this option.
--exclude-from=filename
Treat each non-empty line of the file as the data for an
--exclude option. What constitutes a newline when reading the
file is the operating system's default. The --newline option
has no effect on this option. This option may be given more
than once in order to specify a number of files to read.
--exclude-dir=pattern
Directories whose names match the pattern are skipped without
being processed, whatever the setting of the --recursive
option. This applies to all directories, whether listed on
the command line, obtained from --file-list, or by scanning a
parent directory. The pattern is a PCRE2 regular expression,
and is matched against the final component of the directory
name, not the entire path. The -F, -w, and -x options do not
apply to this pattern. The option may be given any number of
times in order to specify more than one pattern. If a direc-
tory matches both --include-dir and --exclude-dir, it is
excluded. There is no short form for this option.
-F, --fixed-strings
Interpret each data-matching pattern as a list of fixed
strings, separated by newlines, instead of as a regular
expression. What constitutes a newline for this purpose is
controlled by the --newline option. The -w (match as a word)
and -x (match whole line) options can be used with -F. They
apply to each of the fixed strings. A line is selected if any
of the fixed strings are found in it (subject to -w or -x, if
present). This option applies only to the patterns that are
matched against the contents of files; it does not apply to
patterns specified by any of the --include or --exclude
options.
-f filename, --file=filename
Read patterns from the file, one per line, and match them
against each line of input. What constitutes a newline when
reading the file is the operating system's default. The
--newline option has no effect on this option. Trailing white
space is removed from each line, and blank lines are ignored.
An empty file contains no patterns and therefore matches
nothing. See also the comments about multiple patterns versus
a single pattern with alternatives in the description of -e
above.
If this option is given more than once, all the specified
files are read. A data line is output if any of the patterns
match it. A filename can be given as "-" to refer to the
standard input. When -f is used, patterns specified on the
command line using -e may also be present; they are tested
before the file's patterns. However, no other pattern is
taken from the command line; all arguments are treated as the
names of paths to be searched.
--file-list=filename
Read a list of files and/or directories that are to be
scanned from the given file, one per line. Trailing white
space is removed from each line, and blank lines are ignored.
These paths are processed before any that are listed on the
command line. The filename can be given as "-" to refer to
the standard input. If --file and --file-list are both spec-
ified as "-", patterns are read first. This is useful only
when the standard input is a terminal, from which further
lines (the list of files) can be read after an end-of-file
indication. If this option is given more than once, all the
specified files are read.
--file-offsets
Instead of showing lines or parts of lines that match, show
each match as an offset from the start of the file and a
length, separated by a comma. In this mode, no context is
shown. That is, the -A, -B, and -C options are ignored. If
there is more than one match in a line, each of them is shown
separately. This option is mutually exclusive with --line-
offsets and --only-matching.
-H, --with-filename
Force the inclusion of the filename at the start of output
lines when searching a single file. By default, the filename
is not shown in this case. For matching lines, the filename
is followed by a colon; for context lines, a hyphen separator
is used. If a line number is also being output, it follows
the file name.
-h, --no-filename
Suppress the output filenames when searching multiple files.
By default, filenames are shown when multiple files are
searched. For matching lines, the filename is followed by a
colon; for context lines, a hyphen separator is used. If a
line number is also being output, it follows the file name.
--help Output a help message, giving brief details of the command
options and file type support, and then exit. Anything else
on the command line is ignored.
-I Treat binary files as never matching. This is equivalent to
--binary-files=without-match.
-i, --ignore-case
Ignore upper/lower case distinctions during comparisons.
--include=pattern
If any --include patterns are specified, the only files that
are processed are those that match one of the patterns (and
do not match an --exclude pattern). This option does not
affect directories, but it applies to all files, whether
listed on the command line, obtained from --file-list, or by
scanning a directory. The pattern is a PCRE2 regular expres-
sion, and is matched against the final component of the file
name, not the entire path. The -F, -w, and -x options do not
apply to this pattern. The option may be given any number of
times. If a file name matches both an --include and an
--exclude pattern, it is excluded. There is no short form
for this option.
--include-from=filename
Treat each non-empty line of the file as the data for an
--include option. What constitutes a newline for this purpose
is the operating system's default. The --newline option has
no effect on this option. This option may be given any number
of times; all the files are read.
--include-dir=pattern
If any --include-dir patterns are specified, the only direc-
tories that are processed are those that match one of the
patterns (and do not match an --exclude-dir pattern). This
applies to all directories, whether listed on the command
line, obtained from --file-list, or by scanning a parent
directory. The pattern is a PCRE2 regular expression, and is
matched against the final component of the directory name,
not the entire path. The -F, -w, and -x options do not apply
to this pattern. The option may be given any number of times.
If a directory matches both --include-dir and --exclude-dir,
it is excluded. There is no short form for this option.
-L, --files-without-match
Instead of outputting lines from the files, just output the
names of the files that do not contain any lines that would
have been output. Each file name is output once, on a sepa-
rate line.
-l, --files-with-matches
Instead of outputting lines from the files, just output the
names of the files containing lines that would have been out-
put. Each file name is output once, on a separate line.
Searching normally stops as soon as a matching line is found
in a file. However, if the -c (count) option is also used,
matching continues in order to obtain the correct count, and
those files that have at least one match are listed along
with their counts. Using this option with -c is a way of sup-
pressing the listing of files with no matches.
--label=name
This option supplies a name to be used for the standard input
when file names are being output. If not supplied, "(standard
input)" is used. There is no short form for this option.
--line-buffered
When this option is given, input is read and processed line
by line, and the output is flushed after each write. By
default, input is read in large chunks, unless pcre2grep can
determine that it is reading from a terminal (which is cur-
rently possible only in Unix-like environments). Output to
terminal is normally automatically flushed by the operating
system. This option can be useful when the input or output is
attached to a pipe and you do not want pcre2grep to buffer up
large amounts of data. However, its use will affect perfor-
mance, and the -M (multiline) option ceases to work.
--line-offsets
Instead of showing lines or parts of lines that match, show
each match as a line number, the offset from the start of the
line, and a length. The line number is terminated by a colon
(as usual; see the -n option), and the offset and length are
separated by a comma. In this mode, no context is shown.
That is, the -A, -B, and -C options are ignored. If there is
more than one match in a line, each of them is shown sepa-
rately. This option is mutually exclusive with --file-offsets
and --only-matching.
--locale=locale-name
This option specifies a locale to be used for pattern match-
ing. It overrides the value in the LC_ALL or LC_CTYPE envi-
ronment variables. If no locale is specified, the PCRE2
library's default (usually the "C" locale) is used. There is
no short form for this option.
--match-limit=number
Processing some regular expression patterns can require a
very large amount of memory, leading in some cases to a pro-
gram crash if not enough is available. Other patterns may
take a very long time to search for all possible matching
strings. The pcre2_exec() function that is called by
pcre2grep to do the matching has two parameters that can
limit the resources that it uses.
The --match-limit option provides a means of limiting
resource usage when processing patterns that are not going to
match, but which have a very large number of possibilities in
their search trees. The classic example is a pattern that
uses nested unlimited repeats. Internally, PCRE2 uses a func-
tion called match() which it calls repeatedly (sometimes
recursively). The limit set by --match-limit is imposed on
the number of times this function is called during a match,
which has the effect of limiting the amount of backtracking
that can take place.
The --recursion-limit option is similar to --match-limit, but
instead of limiting the total number of times that match() is
called, it limits the depth of recursive calls, which in turn
limits the amount of memory that can be used. The recursion
depth is a smaller number than the total number of calls,
because not all calls to match() are recursive. This limit is
of use only if it is set smaller than --match-limit.
There are no short forms for these options. The default set-
tings are specified when the PCRE2 library is compiled, with
the default default being 10 million.
-M, --multiline
Allow patterns to match more than one line. When this option
is given, patterns may usefully contain literal newline char-
acters and internal occurrences of ^ and $ characters. The
output for a successful match may consist of more than one
line, the last of which is the one in which the match ended.
If the matched string ends with a newline sequence the output
ends at the end of that line.
When this option is set, the PCRE2 library is called in "mul-
tiline" mode. There is a limit to the number of lines that
can be matched, imposed by the way that pcre2grep buffers the
input file as it scans it. However, pcre2grep ensures that at
least 8K characters or the rest of the document (whichever is
the shorter) are available for forward matching, and simi-
larly the previous 8K characters (or all the previous charac-
ters, if fewer than 8K) are guaranteed to be available for
lookbehind assertions. This option does not work when input
is read line by line (see --line-buffered.)
-N newline-type, --newline=newline-type
The PCRE2 library supports five different conventions for
indicating the ends of lines. They are the single-character
sequences CR (carriage return) and LF (linefeed), the two-
character sequence CRLF, an "anycrlf" convention, which rec-
ognizes any of the preceding three types, and an "any" con-
vention, in which any Unicode line ending sequence is assumed
to end a line. The Unicode sequences are the three just men-
tioned, plus VT (vertical tab, U+000B), FF (form feed,
U+000C), NEL (next line, U+0085), LS (line separator,
U+2028), and PS (paragraph separator, U+2029).
When the PCRE2 library is built, a default line-ending
sequence is specified. This is normally the standard
sequence for the operating system. Unless otherwise specified
by this option, pcre2grep uses the library's default. The
possible values for this option are CR, LF, CRLF, ANYCRLF, or
ANY. This makes it possible to use pcre2grep to scan files
that have come from other environments without having to mod-
ify their line endings. If the data that is being scanned
does not agree with the convention set by this option,
pcre2grep may behave in strange ways. Note that this option
does not apply to files specified by the -f, --exclude-from,
or --include-from options, which are expected to use the
operating system's standard newline sequence.
-n, --line-number
Precede each output line by its line number in the file, fol-
lowed by a colon for matching lines or a hyphen for context
lines. If the filename is also being output, it precedes the
line number. This option is forced if --line-offsets is used.
--no-jit If the PCRE2 library is built with support for just-in-time
compiling (which speeds up matching), pcre2grep automatically
makes use of this, unless it was explicitly disabled at build
time. This option can be used to disable the use of JIT at
run time. It is provided for testing and working round prob-
lems. It should never be needed in normal use.
-o, --only-matching
Show only the part of the line that matched a pattern instead
of the whole line. In this mode, no context is shown. That
is, the -A, -B, and -C options are ignored. If there is more
than one match in a line, each of them is shown separately.
If -o is combined with -v (invert the sense of the match to
find non-matching lines), no output is generated, but the
return code is set appropriately. If the matched portion of
the line is empty, nothing is output unless the file name or
line number are being printed, in which case they are shown
on an otherwise empty line. This option is mutually exclusive
with --file-offsets and --line-offsets.
-onumber, --only-matching=number
Show only the part of the line that matched the capturing
parentheses of the given number. Up to 32 capturing parenthe-
ses are supported, and -o0 is equivalent to -o without a num-
ber. Because these options can be given without an argument
(see above), if an argument is present, it must be given in
the same shell item, for example, -o3 or --only-matching=2.
The comments given for the non-argument case above also apply
to this case. If the specified capturing parentheses do not
exist in the pattern, or were not set in the match, nothing
is output unless the file name or line number are being
printed.
If this option is given multiple times, multiple substrings
are output, in the order the options are given. For example,
-o3 -o1 -o3 causes the substrings matched by capturing paren-
theses 3 and 1 and then 3 again to be output. By default,
there is no separator (but see the next option).
--om-separator=text
Specify a separating string for multiple occurrences of -o.
The default is an empty string. Separating strings are never
coloured.
-q, --quiet
Work quietly, that is, display nothing except error messages.
The exit status indicates whether or not any matches were
found.
-r, --recursive
If any given path is a directory, recursively scan the files
it contains, taking note of any --include and --exclude set-
tings. By default, a directory is read as a normal file; in
some operating systems this gives an immediate end-of-file.
This option is a shorthand for setting the -d option to
"recurse".
--recursion-limit=number
See --match-limit above.
-s, --no-messages
Suppress error messages about non-existent or unreadable
files. Such files are quietly skipped. However, the return
code is still 2, even if matches were found in other files.
-u, --utf-8
Operate in UTF-8 mode. This option is available only if PCRE2
has been compiled with UTF-8 support. All patterns (including
those for any --exclude and --include options) and all sub-
ject lines that are scanned must be valid strings of UTF-8
characters.
-V, --version
Write the version numbers of pcre2grep and the PCRE2 library
to the standard output and then exit. Anything else on the
command line is ignored.
-v, --invert-match
Invert the sense of the match, so that lines which do not
match any of the patterns are the ones that are found.
-w, --word-regex, --word-regexp
Force the patterns to match only whole words. This is equiva-
lent to having \b at the start and end of the pattern. This
option applies only to the patterns that are matched against
the contents of files; it does not apply to patterns speci-
fied by any of the --include or --exclude options.
-x, --line-regex, --line-regexp
Force the patterns to be anchored (each must start matching
at the beginning of a line) and in addition, require them to
match entire lines. This is equivalent to having ^ and $
characters at the start and end of each alternative branch in
every pattern. This option applies only to the patterns that
are matched against the contents of files; it does not apply
to patterns specified by any of the --include or --exclude
options.
ENVIRONMENT VARIABLES
The environment variables LC_ALL and LC_CTYPE are examined, in that
order, for a locale. The first one that is set is used. This can be
overridden by the --locale option. If no locale is set, the PCRE2
library's default (usually the "C" locale) is used.
NEWLINES
The -N (--newline) option allows pcre2grep to scan files with different
newline conventions from the default. Any parts of the input files that
are written to the standard output are copied identically, with what-
ever newline sequences they have in the input. However, the setting of
this option does not affect the interpretation of files specified by
the -f, --exclude-from, or --include-from options, which are assumed to
use the operating system's standard newline sequence, nor does it
affect the way in which pcre2grep writes informational messages to the
standard error and output streams. For these it uses the string "\n" to
indicate newlines, relying on the C I/O library to convert this to an
appropriate sequence.
OPTIONS COMPATIBILITY
Many of the short and long forms of pcre2grep's options are the same as
in the GNU grep program. Any long option of the form --xxx-regexp (GNU
terminology) is also available as --xxx-regex (PCRE2 terminology). How-
ever, the --file-list, --file-offsets, --include-dir, --line-offsets,
--locale, --match-limit, -M, --multiline, -N, --newline, --om-separa-
tor, --recursion-limit, -u, and --utf-8 options are specific to
pcre2grep, as is the use of the --only-matching option with a capturing
parentheses number.
Although most of the common options work the same way, a few are dif-
ferent in pcre2grep. For example, the --include option's argument is a
glob for GNU grep, but a regular expression for pcre2grep. If both the
-c and -l options are given, GNU grep lists only file names, without
counts, but pcre2grep gives the counts.
OPTIONS WITH DATA
There are four different ways in which an option with data can be spec-
ified. If a short form option is used, the data may follow immedi-
ately, or (with one exception) in the next command line item. For exam-
ple:
-f/some/file
-f /some/file
The exception is the -o option, which may appear with or without data.
Because of this, if data is present, it must follow immediately in the
same item, for example -o3.
If a long form option is used, the data may appear in the same command
line item, separated by an equals character, or (with two exceptions)
it may appear in the next command line item. For example:
--file=/some/file
--file /some/file
Note, however, that if you want to supply a file name beginning with ~
as data in a shell command, and have the shell expand ~ to a home
directory, you must separate the file name from the option, because the
shell does not treat ~ specially unless it is at the start of an item.
The exceptions to the above are the --colour (or --color) and --only-
matching options, for which the data is optional. If one of these
options does have data, it must be given in the first form, using an
equals character. Otherwise pcre2grep will assume that it has no data.
MATCHING ERRORS
It is possible to supply a regular expression that takes a very long
time to fail to match certain lines. Such patterns normally involve
nested indefinite repeats, for example: (a+)*\d when matched against a
line of a's with no final digit. The PCRE2 matching function has a
resource limit that causes it to abort in these circumstances. If this
happens, pcre2grep outputs an error message and the line that caused
the problem to the standard error stream. If there are more than 20
such errors, pcre2grep gives up.
The --match-limit option of pcre2grep can be used to set the overall
resource limit; there is a second option called --recursion-limit that
sets a limit on the amount of memory (usually stack) that is used (see
the discussion of these options above).
DIAGNOSTICS
Exit status is 0 if any matches were found, 1 if no matches were found,
and 2 for syntax errors, overlong lines, non-existent or inaccessible
files (even if matches were found in other files) or too many matching
errors. Using the -s option to suppress error messages about inaccessi-
ble files does not affect the return code.
SEE ALSO
pcre2pattern(3), pcre2syntax(3), pcre2test(1).
AUTHOR
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
REVISION
Last updated: 28 September 2014
Copyright (c) 1997-2014 University of Cambridge.

2
src/pcre2grep.c
View File

@ -2997,7 +2997,7 @@ if (colour_option != NULL && strcmp(colour_option, "never") != 0)
}
if (do_colour)
{
char *cs = getenv("pcre2grep_COLOUR");
char *cs = getenv("PCRE2GREP_COLOUR");
if (cs == NULL) cs = getenv("PCRE2GREP_COLOR");
if (cs != NULL) colour_string = cs;
}

4
src/pcre2test.c
View File

@ -5094,9 +5094,9 @@ printf(" 32-bit support\n");
(void)PCRE2_CONFIG(PCRE2_CONFIG_UNICODE, &rc, sizeof(rc));
if (rc != 0)
printf(" UTF support (Unicode version %s)\n", uversion);
printf(" UTF and UCP support (Unicode version %s)\n", uversion);
else
printf(" No UTF support\n");
printf(" No UTF or UCP support\n");
(void)PCRE2_CONFIG(PCRE2_CONFIG_JIT, &rc, sizeof(rc));
if (rc != 0)
{