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Update pcre2grep documentation to give more details of -M matching.

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Philip.Hazel 2015-01-03 17:40:06 +00:00
parent 5a18651441
commit 4819827879
3 changed files with 405 additions and 331 deletions
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@ -67,22 +67,23 @@ 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. standard input can also be referenced by a name consisting of a single hyphen.
For example: For example:
<pre> <pre>
pcre2grep some-pattern /file1 - /file3 pcre2grep some-pattern file1 - file3
</pre> </pre>
By default, each line that matches a pattern is copied to the standard Input files are searched line by line. By default, each line that matches a
output, and if there is more than one file, the file name is output at the pattern is copied to the standard output, and if there is more than one file,
start of each line, followed by a colon. However, there are options that can the file name is output at the start of each line, followed by a colon.
change how <b>pcre2grep</b> behaves. In particular, the <b>-M</b> option makes it However, there are options that can change how <b>pcre2grep</b> behaves. In
possible to search for patterns that span line boundaries. What defines a line particular, the <b>-M</b> option makes it possible to search for strings that
boundary is controlled by the <b>-N</b> (<b>--newline</b>) option. span line boundaries. What defines a line boundary is controlled by the
<b>-N</b> (<b>--newline</b>) option.
</P> </P>
<P> <P>
The amount of memory used for buffering files that are being scanned is 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. 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, The default value for this parameter is specified when <b>pcre2grep</b> is
with the default default being 20K. A block of memory three times this size is built, with the default default being 20K. A block of memory three times this
used (to allow for buffering "before" and "after" lines). An error occurs if a size is used (to allow for buffering "before" and "after" lines). An error
line overflows the buffer. occurs if a line overflows the buffer.
</P> </P>
<P> <P>
Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater. Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater.
@ -184,7 +185,8 @@ 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 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 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 <b>-I</b> option, binary files are not processed at all; they are assumed not to
be of interest. be of interest and are skipped without causing any output or affecting the
return code.
</P> </P>
<P> <P>
<b>--buffer-size=</b><i>number</i> <b>--buffer-size=</b><i>number</i>
@ -198,10 +200,15 @@ This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
</P> </P>
<P> <P>
<b>-c</b>, <b>--count</b> <b>-c</b>, <b>--count</b>
Do not output individual lines from the files that are being scanned; instead Do not output lines from the files that are being scanned; instead output the
output the number of lines that would otherwise have been shown. If no lines number of matches (or non-matches if <b>-v</b> is used) that would otherwise
are selected, the number zero is output. If several files are are being have caused lines to be shown. By default, this count is the same as the number
scanned, a count is output for each of them. However, if the of suppressed lines, but if the <b>-M</b> (multiline) option is used (without
<b>-v</b>), there may be more suppressed lines than the number of matches.
<br>
<br>
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 <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>, 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. <b>-B</b>, and <b>-C</b> options are ignored.
@ -271,10 +278,10 @@ of the line that matched.
Files (but not directories) whose names match the pattern are skipped without 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, 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 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 PCRE2 regular expression, and is matched against the final component of the
name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not file name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do
apply to this pattern. The option may be given any number of times in order to not apply to this pattern. The option may be given any number of times in order
specify multiple patterns. If a file name matches both an <b>--include</b> 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 and an <b>--exclude</b> pattern, it is excluded. There is no short form for this
option. option.
</P> </P>
@ -352,11 +359,12 @@ and <b>--only-matching</b>.
</P> </P>
<P> <P>
<b>-H</b>, <b>--with-filename</b> <b>-H</b>, <b>--with-filename</b>
Force the inclusion of the filename at the start of output lines when searching Force the inclusion of the file name at the start of output lines when
a single file. By default, the filename is not shown in this case. For matching searching a single file. By default, the file name is not shown in this case.
lines, the filename is followed by a colon; for context lines, a hyphen For matching lines, the file name is followed by a colon; for context lines, a
separator is used. If a line number is also being output, it follows the file hyphen separator is used. If a line number is also being output, it follows the
name. file name. When the <b>-M</b> option causes a pattern to match more than one
line, only the first is preceded by the file name.
</P> </P>
<P> <P>
<b>-h</b>, <b>--no-filename</b> <b>-h</b>, <b>--no-filename</b>
@ -373,7 +381,7 @@ ignored.
</P> </P>
<P> <P>
<b>-I</b> <b>-I</b>
Treat binary files as never matching. This is equivalent to Ignore binary files. This is equivalent to
<b>--binary-files</b>=<i>without-match</i>. <b>--binary-files</b>=<i>without-match</i>.
</P> </P>
<P> <P>
@ -406,8 +414,8 @@ 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 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 <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 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 directory. The pattern is a PCRE2 regular expression, and is matched against
final component of the directory name, not the entire path. The <b>-F</b>, 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 <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 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. <b>--exclude-dir</b>, it is excluded. There is no short form for this option.
@ -442,8 +450,8 @@ 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 is currently possible only in Unix-like environments). Output to terminal is
normally automatically flushed by the operating system. This option can be 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 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 <b>pcre2grep</b> to buffer up large amounts of data. However, its use will
performance, and the <b>-M</b> (multiline) option ceases to work. affect performance, and the <b>-M</b> (multiline) option ceases to work.
</P> </P>
<P> <P>
<b>--line-offsets</b> <b>--line-offsets</b>
@ -497,18 +505,33 @@ when the PCRE2 library is compiled, with the default default being 10 million.
Allow patterns to match more than one line. When this option is given, patterns Allow patterns to match more than one line. When this option is given, patterns
may usefully contain literal newline characters and internal occurrences of ^ may usefully contain literal newline characters and internal occurrences of ^
and $ characters. The output for a successful match may consist of more than 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 one line. The first is the line in which the match started, and the last is the
string ends with a newline sequence the output ends at the end of that line. line 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>
<br> <br>
When this option is set, the PCRE2 library is called in "multiline" mode. When this option is set, the PCRE2 library is called in "multiline" mode.
However, <b>pcre2grep</b> still processes the input line by line. The difference
is that a matched string may extend past the end of a line and continue on
one or more subsequent lines. The newline sequence must be matched as part of
the pattern. For example, to find the phrase "regular expression" in a file
where "regular" might be at the end of a line and "expression" at the start of
the next line, you could use this command:
<pre>
pcre2grep -M 'regular\s+expression' &#60;file&#62;
</pre>
The \s escape sequence matches any white space character, including newlines,
and is followed by + so as to match trailing white space on the first line as
well as possibly handling a two-character newline sequence.
<br>
<br>
There is a limit to the number of lines that can be matched, imposed by the way 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, 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 <b>pcre2grep</b> ensures that at least 8K characters or the rest of the file
(whichever is the shorter) are available for forward matching, and similarly (whichever is the shorter) are available for forward matching, and similarly
the previous 8K characters (or all the previous characters, if fewer than 8K) 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 are guaranteed to be available for lookbehind assertions. The <b>-M</b> option
work when input is read line by line (see \fP--line-buffered\fP.) does not work when input is read line by line (see \fP--line-buffered\fP.)
</P> </P>
<P> <P>
<b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i> <b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i>
@ -526,9 +549,9 @@ When the PCRE2 library is built, a default line-ending sequence is specified.
This is normally the standard sequence for the operating system. Unless This is normally the standard sequence for the operating system. Unless
otherwise specified by this option, <b>pcre2grep</b> uses the library's default. 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 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 makes it possible to use <b>pcre2grep</b> to scan files that have come from
environments without having to modify their line endings. If the data that is other environments without having to modify their line endings. If the data
being scanned does not agree with the convention set by this option, 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 <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 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 <b>--include-from</b> options, which are expected to use the operating system's
@ -537,9 +560,10 @@ standard newline sequence.
<P> <P>
<b>-n</b>, <b>--line-number</b> <b>-n</b>, <b>--line-number</b>
Precede each output line by its line number in the file, followed by a colon 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 for matching lines or a hyphen for context lines. If the file name is also
output, it precedes the line number. This option is forced if being output, it precedes the line number. When the <b>-M</b> option causes a
<b>--line-offsets</b> is used. pattern to match more than one line, only the first is preceded by its line
number. This option is forced if <b>--line-offsets</b> is used.
</P> </P>
<P> <P>
<b>--no-jit</b> <b>--no-jit</b>
@ -570,7 +594,7 @@ 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 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 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 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. match, nothing is output unless the file name or line number are being output.
<br> <br>
<br> <br>
If this option is given multiple times, multiple substrings are output, in the If this option is given multiple times, multiple substrings are output, in the
@ -635,10 +659,10 @@ specified by any of the <b>--include</b> or <b>--exclude</b> options.
<b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b> <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 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 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 to having ^ and $ characters at the start and end of each alternative top-level
every pattern. This option applies only to the patterns that are matched branch in every pattern. This option applies only to the patterns that are
against the contents of files; it does not apply to patterns specified by any matched against the contents of files; it does not apply to patterns specified
of the <b>--include</b> or <b>--exclude</b> options. by any of the <b>--include</b> or <b>--exclude</b> options.
</P> </P>
<br><a name="SEC6" href="#TOC1">ENVIRONMENT VARIABLES</a><br> <br><a name="SEC6" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
<P> <P>
@ -677,7 +701,7 @@ 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 <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 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, <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. without counts, but <b>pcre2grep</b> gives the counts as well.
</P> </P>
<br><a name="SEC9" href="#TOC1">OPTIONS WITH DATA</a><br> <br><a name="SEC9" href="#TOC1">OPTIONS WITH DATA</a><br>
<P> <P>
@ -722,9 +746,9 @@ 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. there are more than 20 such errors, <b>pcre2grep</b> gives up.
</P> </P>
<P> <P>
The <b>--match-limit</b> option of <b>pcre2grep</b> can be used to set the overall The <b>--match-limit</b> option of <b>pcre2grep</b> can be used to set the
resource limit; there is a second option called <b>--recursion-limit</b> that overall resource limit; there is a second option called <b>--recursion-limit</b>
sets a limit on the amount of memory (usually stack) that is used (see the that sets a limit on the amount of memory (usually stack) that is used (see the
discussion of these options above). discussion of these options above).
</P> </P>
<br><a name="SEC11" href="#TOC1">DIAGNOSTICS</a><br> <br><a name="SEC11" href="#TOC1">DIAGNOSTICS</a><br>
@ -737,7 +761,7 @@ affect the return code.
</P> </P>
<br><a name="SEC12" href="#TOC1">SEE ALSO</a><br> <br><a name="SEC12" href="#TOC1">SEE ALSO</a><br>
<P> <P>
<b>pcre2pattern</b>(3), <b>pcre2syntax</b>(3), <b>pcre2test</b>(1). <b>pcre2pattern</b>(3), <b>pcre2syntax</b>(3).
</P> </P>
<br><a name="SEC13" href="#TOC1">AUTHOR</a><br> <br><a name="SEC13" href="#TOC1">AUTHOR</a><br>
<P> <P>
@ -750,9 +774,9 @@ Cambridge, England.
</P> </P>
<br><a name="SEC14" href="#TOC1">REVISION</a><br> <br><a name="SEC14" href="#TOC1">REVISION</a><br>
<P> <P>
Last updated: 23 November 2014 Last updated: 03 January 2015
<br> <br>
Copyright &copy; 1997-2014 University of Cambridge. Copyright &copy; 1997-2015 University of Cambridge.
<br> <br>
<p> <p>
Return to the <a href="index.html">PCRE2 index page</a>. Return to the <a href="index.html">PCRE2 index page</a>.

130
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@ -1,4 +1,4 @@
.TH PCRE2GREP 1 "23 November 2014" "PCRE2 10.00" .TH PCRE2GREP 1 "03 January 2015" "PCRE2 10.00"
.SH NAME .SH NAME
pcre2grep - a grep with Perl-compatible regular expressions. pcre2grep - a grep with Perl-compatible regular expressions.
.SH SYNOPSIS .SH SYNOPSIS
@ -41,21 +41,22 @@ 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. standard input can also be referenced by a name consisting of a single hyphen.
For example: For example:
.sp .sp
pcre2grep some-pattern /file1 - /file3 pcre2grep some-pattern file1 - file3
.sp .sp
By default, each line that matches a pattern is copied to the standard Input files are searched line by line. By default, each line that matches a
output, and if there is more than one file, the file name is output at the pattern is copied to the standard output, and if there is more than one file,
start of each line, followed by a colon. However, there are options that can the file name is output at the start of each line, followed by a colon.
change how \fBpcre2grep\fP behaves. In particular, the \fB-M\fP option makes it However, there are options that can change how \fBpcre2grep\fP behaves. In
possible to search for patterns that span line boundaries. What defines a line particular, the \fB-M\fP option makes it possible to search for strings that
boundary is controlled by the \fB-N\fP (\fB--newline\fP) option. span line boundaries. What defines a line boundary is controlled by the
\fB-N\fP (\fB--newline\fP) option.
.P .P
The amount of memory used for buffering files that are being scanned is 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. 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, The default value for this parameter is specified when \fBpcre2grep\fP is
with the default default being 20K. A block of memory three times this size is built, with the default default being 20K. A block of memory three times this
used (to allow for buffering "before" and "after" lines). An error occurs if a size is used (to allow for buffering "before" and "after" lines). An error
line overflows the buffer. occurs if a line overflows the buffer.
.P .P
Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater. 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 BUFSIZ is defined in \fB<stdio.h>\fP. When there is more than one pattern
@ -153,7 +154,8 @@ 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 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 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 \fB-I\fP option, binary files are not processed at all; they are assumed not to
be of interest. be of interest and are skipped without causing any output or affecting the
return code.
.TP .TP
\fB--buffer-size=\fP\fInumber\fP \fB--buffer-size=\fP\fInumber\fP
Set the parameter that controls how much memory is used for buffering files Set the parameter that controls how much memory is used for buffering files
@ -164,10 +166,14 @@ 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. This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
.TP .TP
\fB-c\fP, \fB--count\fP \fB-c\fP, \fB--count\fP
Do not output individual lines from the files that are being scanned; instead Do not output lines from the files that are being scanned; instead output the
output the number of lines that would otherwise have been shown. If no lines number of matches (or non-matches if \fB-v\fP is used) that would otherwise
are selected, the number zero is output. If several files are are being have caused lines to be shown. By default, this count is the same as the number
scanned, a count is output for each of them. However, if the of suppressed lines, but if the \fB-M\fP (multiline) option is used (without
\fB-v\fP), there may be more suppressed lines than the number of matches.
.sp
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 \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, 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. \fB-B\fP, and \fB-C\fP options are ignored.
@ -229,10 +235,10 @@ of the line that matched.
Files (but not directories) whose names match the pattern are skipped without 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, 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 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 PCRE2 regular expression, and is matched against the final component of the
name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do not file name, not the entire path. The \fB-F\fP, \fB-w\fP, and \fB-x\fP options do
apply to this pattern. The option may be given any number of times in order to not apply to this pattern. The option may be given any number of times in order
specify multiple patterns. If a file name matches both an \fB--include\fP 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 and an \fB--exclude\fP pattern, it is excluded. There is no short form for this
option. option.
.TP .TP
@ -302,11 +308,12 @@ shown separately. This option is mutually exclusive with \fB--line-offsets\fP
and \fB--only-matching\fP. and \fB--only-matching\fP.
.TP .TP
\fB-H\fP, \fB--with-filename\fP \fB-H\fP, \fB--with-filename\fP
Force the inclusion of the filename at the start of output lines when searching Force the inclusion of the file name at the start of output lines when
a single file. By default, the filename is not shown in this case. For matching searching a single file. By default, the file name is not shown in this case.
lines, the filename is followed by a colon; for context lines, a hyphen For matching lines, the file name is followed by a colon; for context lines, a
separator is used. If a line number is also being output, it follows the file hyphen separator is used. If a line number is also being output, it follows the
name. file name. When the \fB-M\fP option causes a pattern to match more than one
line, only the first is preceded by the file name.
.TP .TP
\fB-h\fP, \fB--no-filename\fP \fB-h\fP, \fB--no-filename\fP
Suppress the output file names when searching multiple files. By default, Suppress the output file names when searching multiple files. By default,
@ -320,7 +327,7 @@ type support, and then exit. Anything else on the command line is
ignored. ignored.
.TP .TP
\fB-I\fP \fB-I\fP
Treat binary files as never matching. This is equivalent to Ignore binary files. This is equivalent to
\fB--binary-files\fP=\fIwithout-match\fP. \fB--binary-files\fP=\fIwithout-match\fP.
.TP .TP
\fB-i\fP, \fB--ignore-case\fP \fB-i\fP, \fB--ignore-case\fP
@ -349,8 +356,8 @@ 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 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 \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 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 directory. The pattern is a PCRE2 regular expression, and is matched against
final component of the directory name, not the entire path. The \fB-F\fP, 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 \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 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. \fB--exclude-dir\fP, it is excluded. There is no short form for this option.
@ -381,8 +388,8 @@ 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 is currently possible only in Unix-like environments). Output to terminal is
normally automatically flushed by the operating system. This option can be 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 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 \fBpcre2grep\fP to buffer up large amounts of data. However, its use will
performance, and the \fB-M\fP (multiline) option ceases to work. affect performance, and the \fB-M\fP (multiline) option ceases to work.
.TP .TP
\fB--line-offsets\fP \fB--line-offsets\fP
Instead of showing lines or parts of lines that match, show each match as a Instead of showing lines or parts of lines that match, show each match as a
@ -429,17 +436,31 @@ when the PCRE2 library is compiled, with the default default being 10 million.
Allow patterns to match more than one line. When this option is given, patterns Allow patterns to match more than one line. When this option is given, patterns
may usefully contain literal newline characters and internal occurrences of ^ may usefully contain literal newline characters and internal occurrences of ^
and $ characters. The output for a successful match may consist of more than 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 one line. The first is the line in which the match started, and the last is the
string ends with a newline sequence the output ends at the end of that line. line in which the match ended. If the matched string ends with a newline
sequence the output ends at the end of that line.
.sp .sp
When this option is set, the PCRE2 library is called in "multiline" mode. When this option is set, the PCRE2 library is called in "multiline" mode.
However, \fBpcre2grep\fP still processes the input line by line. The difference
is that a matched string may extend past the end of a line and continue on
one or more subsequent lines. The newline sequence must be matched as part of
the pattern. For example, to find the phrase "regular expression" in a file
where "regular" might be at the end of a line and "expression" at the start of
the next line, you could use this command:
.sp
pcre2grep -M 'regular\es+expression' <file>
.sp
The \es escape sequence matches any white space character, including newlines,
and is followed by + so as to match trailing white space on the first line as
well as possibly handling a two-character newline sequence.
.sp
There is a limit to the number of lines that can be matched, imposed by the way 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, 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 \fBpcre2grep\fP ensures that at least 8K characters or the rest of the file
(whichever is the shorter) are available for forward matching, and similarly (whichever is the shorter) are available for forward matching, and similarly
the previous 8K characters (or all the previous characters, if fewer than 8K) 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 are guaranteed to be available for lookbehind assertions. The \fB-M\fP option
work when input is read line by line (see \fP--line-buffered\fP.) does not work when input is read line by line (see \fP--line-buffered\fP.)
.TP .TP
\fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP \fB-N\fP \fInewline-type\fP, \fB--newline\fP=\fInewline-type\fP
The PCRE2 library supports five different conventions for indicating The PCRE2 library supports five different conventions for indicating
@ -455,9 +476,9 @@ When the PCRE2 library is built, a default line-ending sequence is specified.
This is normally the standard sequence for the operating system. Unless This is normally the standard sequence for the operating system. Unless
otherwise specified by this option, \fBpcre2grep\fP uses the library's default. 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 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 makes it possible to use \fBpcre2grep\fP to scan files that have come from
environments without having to modify their line endings. If the data that is other environments without having to modify their line endings. If the data
being scanned does not agree with the convention set by this option, 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 \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 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 \fB--include-from\fP options, which are expected to use the operating system's
@ -465,9 +486,10 @@ standard newline sequence.
.TP .TP
\fB-n\fP, \fB--line-number\fP \fB-n\fP, \fB--line-number\fP
Precede each output line by its line number in the file, followed by a colon 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 for matching lines or a hyphen for context lines. If the file name is also
output, it precedes the line number. This option is forced if being output, it precedes the line number. When the \fB-M\fP option causes a
\fB--line-offsets\fP is used. pattern to match more than one line, only the first is preceded by its line
number. This option is forced if \fB--line-offsets\fP is used.
.TP .TP
\fB--no-jit\fP \fB--no-jit\fP
If the PCRE2 library is built with support for just-in-time compiling (which If the PCRE2 library is built with support for just-in-time compiling (which
@ -495,7 +517,7 @@ 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 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 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 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. match, nothing is output unless the file name or line number are being output.
.sp .sp
If this option is given multiple times, multiple substrings are output, in the 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 order the options are given. For example, -o3 -o1 -o3 causes the substrings
@ -549,10 +571,10 @@ specified by any of the \fB--include\fP or \fB--exclude\fP options.
\fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP \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 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 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 to having ^ and $ characters at the start and end of each alternative top-level
every pattern. This option applies only to the patterns that are matched branch in every pattern. This option applies only to the patterns that are
against the contents of files; it does not apply to patterns specified by any matched against the contents of files; it does not apply to patterns specified
of the \fB--include\fP or \fB--exclude\fP options. by any of the \fB--include\fP or \fB--exclude\fP options.
. .
. .
.SH "ENVIRONMENT VARIABLES" .SH "ENVIRONMENT VARIABLES"
@ -596,7 +618,7 @@ 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 \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 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, \fB-c\fP and \fB-l\fP options are given, GNU grep lists only file names,
without counts, but \fBpcre2grep\fP gives the counts. without counts, but \fBpcre2grep\fP gives the counts as well.
. .
. .
.SH "OPTIONS WITH DATA" .SH "OPTIONS WITH DATA"
@ -642,9 +664,9 @@ 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 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. there are more than 20 such errors, \fBpcre2grep\fP gives up.
.P .P
The \fB--match-limit\fP option of \fBpcre2grep\fP can be used to set the overall The \fB--match-limit\fP option of \fBpcre2grep\fP can be used to set the
resource limit; there is a second option called \fB--recursion-limit\fP that overall resource limit; there is a second option called \fB--recursion-limit\fP
sets a limit on the amount of memory (usually stack) that is used (see the that sets a limit on the amount of memory (usually stack) that is used (see the
discussion of these options above). discussion of these options above).
. .
. .
@ -661,7 +683,7 @@ affect the return code.
.SH "SEE ALSO" .SH "SEE ALSO"
.rs .rs
.sp .sp
\fBpcre2pattern\fP(3), \fBpcre2syntax\fP(3), \fBpcre2test\fP(1). \fBpcre2pattern\fP(3), \fBpcre2syntax\fP(3).
. .
. .
.SH AUTHOR .SH AUTHOR
@ -678,6 +700,6 @@ Cambridge, England.
.rs .rs
.sp .sp
.nf .nf
Last updated: 23 November 2014 Last updated: 03 January 2015
Copyright (c) 1997-2014 University of Cambridge. Copyright (c) 1997-2015 University of Cambridge.
.fi .fi

126
doc/pcre2grep.txt
View File

@ -40,15 +40,15 @@ DESCRIPTION
standard input can also be referenced by a name consisting of a single standard input can also be referenced by a name consisting of a single
hyphen. For example: hyphen. For example:
pcre2grep some-pattern /file1 - /file3 pcre2grep some-pattern file1 - file3
By default, each line that matches a pattern is copied to the standard Input files are searched line by line. By default, each line that
output, and if there is more than one file, the file name is output at matches a pattern is copied to the standard output, and if there is
the start of each line, followed by a colon. However, there are options more than one file, the file name is output at the start of each line,
that can change how pcre2grep behaves. In particular, the -M option followed by a colon. However, there are options that can change how
makes it possible to search for patterns that span line boundaries. pcre2grep behaves. In particular, the -M option makes it possible to
What defines a line boundary is controlled by the -N (--newline) search for strings that span line boundaries. What defines a line
option. boundary is controlled by the -N (--newline) option.
The amount of memory used for buffering files that are being scanned is 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. controlled by a parameter that can be set by the --buffer-size option.
@ -122,13 +122,13 @@ OPTIONS
-- This terminates the list of options. It is useful if the next -- 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 item on the command line starts with a hyphen but is not an
option. This allows for the processing of patterns and file- option. This allows for the processing of patterns and file
names that start with hyphens. names that start with hyphens.
-A number, --after-context=number -A number, --after-context=number
Output number lines of context after each matching line. If Output number lines of context after each matching line. If
filenames and/or line numbers are being output, a hyphen sep- file names and/or line numbers are being output, a hyphen
arator is used instead of a colon for the context lines. A separator is used instead of a colon for the context lines. A
line containing "--" is output between each group of lines, line containing "--" is output between each group of lines,
unless they are in fact contiguous in the input file. The unless they are in fact contiguous in the input file. The
value of number is expected to be relatively small. However, value of number is expected to be relatively small. However,
@ -141,8 +141,8 @@ OPTIONS
-B number, --before-context=number -B number, --before-context=number
Output number lines of context before each matching line. If Output number lines of context before each matching line. If
filenames and/or line numbers are being output, a hyphen sep- file names and/or line numbers are being output, a hyphen
arator is used instead of a colon for the context lines. A separator is used instead of a colon for the context lines. A
line containing "--" is output between each group of lines, line containing "--" is output between each group of lines,
unless they are in fact contiguous in the input file. The unless they are in fact contiguous in the input file. The
value of number is expected to be relatively small. However, value of number is expected to be relatively small. However,
@ -160,7 +160,8 @@ OPTIONS
which can have nasty effects if sent to a terminal. If the which can have nasty effects if sent to a terminal. If the
word is "without-match", which is equivalent to the -I word is "without-match", which is equivalent to the -I
option, binary files are not processed at all; they are option, binary files are not processed at all; they are
assumed not to be of interest. assumed not to be of interest and are skipped without causing
any output or affecting the return code.
--buffer-size=number --buffer-size=number
Set the parameter that controls how much memory is used for Set the parameter that controls how much memory is used for
@ -172,14 +173,20 @@ OPTIONS
to the same value. to the same value.
-c, --count -c, --count
Do not output individual lines from the files that are being Do not output lines from the files that are being scanned;
scanned; instead output the number of lines that would other- instead output the number of matches (or non-matches if -v is
wise have been shown. If no lines are selected, the number used) that would otherwise have caused lines to be shown. By
zero is output. If several files are are being scanned, a default, this count is the same as the number of suppressed
count is output for each of them. However, if the --files- lines, but if the -M (multiline) option is used (without -v),
with-matches option is also used, only those files whose there may be more suppressed lines than the number of
counts are greater than zero are listed. When -c is used, the matches.
-A, -B, and -C options are ignored.
If no lines are selected, the number zero is output. If sev-
eral 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 --colour, --color
If this option is given without any data, it is equivalent to If this option is given without any data, it is equivalent to
@ -336,7 +343,9 @@ OPTIONS
is not shown in this case. For matching lines, the file name is not shown in this case. For matching lines, the file name
is followed by a colon; for context lines, a hyphen separator is followed by a colon; for context lines, a hyphen separator
is used. If a line number is also being output, it follows is used. If a line number is also being output, it follows
the file name. the file name. When the -M option causes a pattern to match
more than one line, only the first is preceded by the file
name.
-h, --no-filename -h, --no-filename
Suppress the output file names when searching multiple files. Suppress the output file names when searching multiple files.
@ -349,8 +358,8 @@ OPTIONS
options and file type support, and then exit. Anything else options and file type support, and then exit. Anything else
on the command line is ignored. on the command line is ignored.
-I Treat binary files as never matching. This is equivalent to -I Ignore binary files. This is equivalent to --binary-
--binary-files=without-match. files=without-match.
-i, --ignore-case -i, --ignore-case
Ignore upper/lower case distinctions during comparisons. Ignore upper/lower case distinctions during comparisons.
@ -478,20 +487,37 @@ OPTIONS
is given, patterns may usefully contain literal newline char- is given, patterns may usefully contain literal newline char-
acters and internal occurrences of ^ and $ characters. The acters and internal occurrences of ^ and $ characters. The
output for a successful match may consist of more than one output for a successful match may consist of more than one
line, the last of which is the one in which the match ended. line. The first is the line in which the match started, and
If the matched string ends with a newline sequence the output the last is the line in which the match ended. If the matched
ends at the end of that line. 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- When this option is set, the PCRE2 library is called in "mul-
tiline" mode. There is a limit to the number of lines that tiline" mode. However, pcre2grep still processes the input
can be matched, imposed by the way that pcre2grep buffers the line by line. The difference is that a matched string may
input file as it scans it. However, pcre2grep ensures that at extend past the end of a line and continue on one or more
least 8K characters or the rest of the document (whichever is subsequent lines. The newline sequence must be matched as
the shorter) are available for forward matching, and simi- part of the pattern. For example, to find the phrase "regular
larly the previous 8K characters (or all the previous charac- expression" in a file where "regular" might be at the end of
ters, if fewer than 8K) are guaranteed to be available for a line and "expression" at the start of the next line, you
lookbehind assertions. This option does not work when input could use this command:
is read line by line (see --line-buffered.)
pcre2grep -M 'regular\s+expression' <file>
The \s escape sequence matches any white space character,
including newlines, and is followed by + so as to match
trailing white space on the first line as well as possibly
handling a two-character newline sequence.
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 file (whichever is the shorter)
are available for forward matching, and similarly the previ-
ous 8K characters (or all the previous characters, if fewer
than 8K) are guaranteed to be available for lookbehind asser-
tions. The -M option does not work when input is read line by
line (see --line-buffered.)
-N newline-type, --newline=newline-type -N newline-type, --newline=newline-type
The PCRE2 library supports five different conventions for The PCRE2 library supports five different conventions for
@ -523,7 +549,9 @@ OPTIONS
Precede each output line by its line number in the file, fol- Precede each output line by its line number in the file, fol-
lowed by a colon for matching lines or a hyphen for context lowed by a colon for matching lines or a hyphen for context
lines. If the file name is also being output, it precedes the lines. If the file name is also being output, it precedes the
line number. This option is forced if --line-offsets is used. line number. When the -M option causes a pattern to match
more than one line, only the first is preceded by its 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 --no-jit If the PCRE2 library is built with support for just-in-time
compiling (which speeds up matching), pcre2grep automatically compiling (which speeds up matching), pcre2grep automatically
@ -555,8 +583,8 @@ OPTIONS
The comments given for the non-argument case above also apply The comments given for the non-argument case above also apply
to this case. If the specified capturing parentheses do not to this case. If the specified capturing parentheses do not
exist in the pattern, or were not set in the match, nothing exist in the pattern, or were not set in the match, nothing
is output unless the file name or line number are being is output unless the file name or line number are being out-
printed. put.
If this option is given multiple times, multiple substrings If this option is given multiple times, multiple substrings
are output, in the order the options are given. For example, are output, in the order the options are given. For example,
@ -617,11 +645,11 @@ OPTIONS
Force the patterns to be anchored (each must start matching Force the patterns to be anchored (each must start matching
at the beginning of a line) and in addition, require them to at the beginning of a line) and in addition, require them to
match entire lines. This is equivalent to having ^ and $ match entire lines. This is equivalent to having ^ and $
characters at the start and end of each alternative branch in characters at the start and end of each alternative top-level
every pattern. This option applies only to the patterns that branch in every pattern. This option applies only to the pat-
are matched against the contents of files; it does not apply terns that are matched against the contents of files; it does
to patterns specified by any of the --include or --exclude not apply to patterns specified by any of the --include or
options. --exclude options.
ENVIRONMENT VARIABLES ENVIRONMENT VARIABLES
@ -662,7 +690,7 @@ OPTIONS COMPATIBILITY
ferent in pcre2grep. For example, the --include option's argument is a 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 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 -c and -l options are given, GNU grep lists only file names, without
counts, but pcre2grep gives the counts. counts, but pcre2grep gives the counts as well.
OPTIONS WITH DATA OPTIONS WITH DATA
@ -725,7 +753,7 @@ DIAGNOSTICS
SEE ALSO SEE ALSO
pcre2pattern(3), pcre2syntax(3), pcre2test(1). pcre2pattern(3), pcre2syntax(3).
AUTHOR AUTHOR
@ -737,5 +765,5 @@ AUTHOR
REVISION REVISION
Last updated: 23 November 2014 Last updated: 03 January 2015
Copyright (c) 1997-2014 University of Cambridge. Copyright (c) 1997-2015 University of Cambridge.