425 lines
19 KiB
HTML
425 lines
19 KiB
HTML
<html>
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<head>
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<title>pcregrep specification</title>
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</head>
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<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
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<h1>pcregrep man page</h1>
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<p>
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Return to the <a href="index.html">PCRE index page</a>.
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</p>
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<p>
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This page is part of the PCRE HTML documentation. It was generated automatically
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from the original man page. If there is any nonsense in it, please consult the
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man page, in case the conversion went wrong.
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<br>
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<ul>
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<li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
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<li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
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<li><a name="TOC3" href="#SEC3">OPTIONS</a>
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<li><a name="TOC4" href="#SEC4">ENVIRONMENT VARIABLES</a>
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<li><a name="TOC5" href="#SEC5">NEWLINES</a>
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<li><a name="TOC6" href="#SEC6">OPTIONS COMPATIBILITY</a>
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<li><a name="TOC7" href="#SEC7">OPTIONS WITH DATA</a>
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<li><a name="TOC8" href="#SEC8">MATCHING ERRORS</a>
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<li><a name="TOC9" href="#SEC9">DIAGNOSTICS</a>
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<li><a name="TOC10" href="#SEC10">AUTHOR</a>
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</ul>
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<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
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<P>
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<b>pcregrep [options] [long options] [pattern] [path1 path2 ...]</b>
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</P>
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<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
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<P>
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<b>pcregrep</b> searches files for character patterns, in the same way as other
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grep commands do, but it uses the PCRE regular expression library to support
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patterns that are compatible with the regular expressions of Perl 5. See
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<a href="pcrepattern.html"><b>pcrepattern</b></a>
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for a full description of syntax and semantics of the regular expressions that
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PCRE supports.
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</P>
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<P>
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Patterns, whether supplied on the command line or in a separate file, are given
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without delimiters. For example:
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<pre>
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pcregrep Thursday /etc/motd
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</pre>
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If you attempt to use delimiters (for example, by surrounding a pattern with
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slashes, as is common in Perl scripts), they are interpreted as part of the
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pattern. Quotes can of course be used on the command line because they are
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interpreted by the shell, and indeed they are required if a pattern contains
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white space or shell metacharacters.
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</P>
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<P>
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The first argument that follows any option settings is treated as the single
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pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present.
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Conversely, when one or both of these options are used to specify patterns, all
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arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an
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argument pattern must be provided.
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</P>
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<P>
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If no files are specified, <b>pcregrep</b> reads the standard input. The
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standard input can also be referenced by a name consisting of a single hyphen.
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For example:
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<pre>
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pcregrep some-pattern /file1 - /file3
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</pre>
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By default, each line that matches the pattern is copied to the standard
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output, and if there is more than one file, the file name is output at the
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start of each line. However, there are options that can change how
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<b>pcregrep</b> behaves. In particular, the <b>-M</b> option makes it possible to
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search for patterns that span line boundaries. What defines a line boundary is
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controlled by the <b>-N</b> (<b>--newline</b>) option.
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</P>
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<P>
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Patterns are limited to 8K or BUFSIZ characters, whichever is the greater.
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BUFSIZ is defined in <b><stdio.h></b>.
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</P>
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<P>
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If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set,
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<b>pcregrep</b> uses the value to set a locale when calling the PCRE library.
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The <b>--locale</b> option can be used to override this.
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</P>
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<br><a name="SEC3" href="#TOC1">OPTIONS</a><br>
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<P>
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<b>--</b>
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This terminate the list of options. It is useful if the next item on the
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command line starts with a hyphen but is not an option. This allows for the
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processing of patterns and filenames that start with hyphens.
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</P>
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<P>
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<b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i>
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Output <i>number</i> lines of context after each matching line. If filenames
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and/or line numbers are being output, a hyphen separator is used instead of a
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colon for the context lines. A line containing "--" is output between each
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group of lines, unless they are in fact contiguous in the input file. The value
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of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
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guarantees to have up to 8K of following text available for context output.
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</P>
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<P>
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<b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i>
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Output <i>number</i> lines of context before each matching line. If filenames
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and/or line numbers are being output, a hyphen separator is used instead of a
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colon for the context lines. A line containing "--" is output between each
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group of lines, unless they are in fact contiguous in the input file. The value
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of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b>
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guarantees to have up to 8K of preceding text available for context output.
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</P>
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<P>
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<b>-C</b> <i>number</i>, <b>--context=</b><i>number</i>
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Output <i>number</i> lines of context both before and after each matching line.
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This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value.
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</P>
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<P>
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<b>-c</b>, <b>--count</b>
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Do not output individual lines; instead just output a count of the number of
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lines that would otherwise have been output. If several files are given, a
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count is output for each of them. In this mode, the <b>-A</b>, <b>-B</b>, and
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<b>-C</b> options are ignored.
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</P>
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<P>
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<b>--colour</b>, <b>--color</b>
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If this option is given without any data, it is equivalent to "--colour=auto".
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If data is required, it must be given in the same shell item, separated by an
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equals sign.
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</P>
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<P>
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<b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i>
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This option specifies under what circumstances the part of a line that matched
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a pattern should be coloured in the output. The value may be "never" (the
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default), "always", or "auto". In the latter case, colouring happens only if
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the standard output is connected to a terminal. The colour can be specified by
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setting the environment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
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of this variable should be a string of two numbers, separated by a semicolon.
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They are copied directly into the control string for setting colour on a
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terminal, so it is your responsibility to ensure that they make sense. If
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neither of the environment variables is set, the default is "1;31", which gives
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red.
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</P>
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<P>
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<b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i>
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If an input path is not a regular file or a directory, "action" specifies how
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it is to be processed. Valid values are "read" (the default) or "skip"
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(silently skip the path).
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</P>
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<P>
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<b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i>
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If an input path is a directory, "action" specifies how it is to be processed.
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Valid values are "read" (the default), "recurse" (equivalent to the <b>-r</b>
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option), or "skip" (silently skip the path). In the default case, directories
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are read as if they were ordinary files. In some operating systems the effect
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of reading a directory like this is an immediate end-of-file.
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</P>
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<P>
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<b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>,
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<b>--regexp=</b><i>pattern</i> Specify a pattern to be matched. This option can
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be used multiple times in order to specify several patterns. It can also be
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used as a way of specifying a single pattern that starts with a hyphen. When
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<b>-e</b> is used, no argument pattern is taken from the command line; all
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arguments are treated as file names. There is an overall maximum of 100
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patterns. They are applied to each line in the order in which they are defined
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until one matches (or fails to match if <b>-v</b> is used). If <b>-f</b> is used
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with <b>-e</b>, the command line patterns are matched first, followed by the
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patterns from the file, independent of the order in which these options are
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specified. Note that multiple use of <b>-e</b> is not the same as a single
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pattern with alternatives. For example, X|Y finds the first character in a line
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that is X or Y, whereas if the two patterns are given separately,
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<b>pcregrep</b> finds X if it is present, even if it follows Y in the line. It
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finds Y only if there is no X in the line. This really matters only if you are
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using <b>-o</b> to show the portion of the line that matched.
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</P>
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<P>
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<b>--exclude</b>=<i>pattern</i>
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When <b>pcregrep</b> is searching the files in a directory as a consequence of
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the <b>-r</b> (recursive search) option, any files whose names match the pattern
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are excluded. The pattern is a PCRE regular expression. If a file name matches
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both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no short
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form for this option.
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</P>
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<P>
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<b>-F</b>, <b>--fixed-strings</b>
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Interpret each pattern as a list of fixed strings, separated by newlines,
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instead of as a regular expression. The <b>-w</b> (match as a word) and <b>-x</b>
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(match whole line) options can be used with <b>-F</b>. They apply to each of the
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fixed strings. A line is selected if any of the fixed strings are found in it
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(subject to <b>-w</b> or <b>-x</b>, if present).
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</P>
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<P>
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<b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i>
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Read a number of patterns from the file, one per line, and match them against
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each line of input. A data line is output if any of the patterns match it. The
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filename can be given as "-" to refer to the standard input. When <b>-f</b> is
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used, patterns specified on the command line using <b>-e</b> may also be
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present; they are tested before the file's patterns. However, no other pattern
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is taken from the command line; all arguments are treated as file names. There
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is an overall maximum of 100 patterns. Trailing white space is removed from
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each line, and blank lines are ignored. An empty file contains no patterns and
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therefore matches nothing.
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</P>
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<P>
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<b>-H</b>, <b>--with-filename</b>
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Force the inclusion of the filename at the start of output lines when searching
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a single file. By default, the filename is not shown in this case. For matching
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lines, the filename is followed by a colon and a space; for context lines, a
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hyphen separator is used. If a line number is also being output, it follows the
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file name without a space.
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</P>
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<P>
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<b>-h</b>, <b>--no-filename</b>
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Suppress the output filenames when searching multiple files. By default,
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filenames are shown when multiple files are searched. For matching lines, the
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filename is followed by a colon and a space; for context lines, a hyphen
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separator is used. If a line number is also being output, it follows the file
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name without a space.
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</P>
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<P>
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<b>--help</b>
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Output a brief help message and exit.
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</P>
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<P>
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<b>-i</b>, <b>--ignore-case</b>
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Ignore upper/lower case distinctions during comparisons.
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</P>
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<P>
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<b>--include</b>=<i>pattern</i>
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When <b>pcregrep</b> is searching the files in a directory as a consequence of
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the <b>-r</b> (recursive search) option, only those files whose names match the
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pattern are included. The pattern is a PCRE regular expression. If a file name
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matches both <b>--include</b> and <b>--exclude</b>, it is excluded. There is no
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short form for this option.
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</P>
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<P>
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<b>-L</b>, <b>--files-without-match</b>
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Instead of outputting lines from the files, just output the names of the files
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that do not contain any lines that would have been output. Each file name is
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output once, on a separate line.
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</P>
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<P>
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<b>-l</b>, <b>--files-with-matches</b>
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Instead of outputting lines from the files, just output the names of the files
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containing lines that would have been output. Each file name is output
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once, on a separate line. Searching stops as soon as a matching line is found
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in a file.
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</P>
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<P>
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<b>--label</b>=<i>name</i>
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This option supplies a name to be used for the standard input when file names
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are being output. If not supplied, "(standard input)" is used. There is no
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short form for this option.
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</P>
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<P>
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<b>--locale</b>=<i>locale-name</i>
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This option specifies a locale to be used for pattern matching. It overrides
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the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no
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locale is specified, the PCRE library's default (usually the "C" locale) is
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used. There is no short form for this option.
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</P>
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<P>
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<b>-M</b>, <b>--multiline</b>
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Allow patterns to match more than one line. When this option is given, patterns
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may usefully contain literal newline characters and internal occurrences of ^
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and $ characters. The output for any one match may consist of more than one
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line. When this option is set, the PCRE library is called in "multiline" mode.
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There is a limit to the number of lines that can be matched, imposed by the way
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that <b>pcregrep</b> buffers the input file as it scans it. However,
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<b>pcregrep</b> ensures that at least 8K characters or the rest of the document
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(whichever is the shorter) are available for forward matching, and similarly
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the previous 8K characters (or all the previous characters, if fewer than 8K)
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are guaranteed to be available for lookbehind assertions.
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</P>
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<P>
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<b>-N</b> <i>newline-type</i>, <b>--newline=</b><i>newline-type</i>
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The PCRE library supports three different character sequences for indicating
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the ends of lines. They are the single-character sequences CR (carriage return)
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and LF (linefeed), and the two-character sequence CR, LF. When the library is
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built, a default line-ending sequence is specified. This is normally the
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standard sequence for the operating system. Unless otherwise specified by this
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option, <b>pcregrep</b> uses the default. The possible values for this option
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are CR, LF, or CRLF. This makes it possible to use <b>pcregrep</b> on files that
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have come from other environments without having to modify their line endings.
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If the data that is being scanned does not agree with the convention set by
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this option, <b>pcregrep</b> may behave in strange ways.
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</P>
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<P>
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<b>-n</b>, <b>--line-number</b>
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Precede each output line by its line number in the file, followed by a colon
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and a space for matching lines or a hyphen and a space for context lines. If
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the filename is also being output, it precedes the line number.
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</P>
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<P>
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<b>-o</b>, <b>--only-matching</b>
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Show only the part of the line that matched a pattern. In this mode, no
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context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are
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ignored.
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</P>
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<P>
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<b>-q</b>, <b>--quiet</b>
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Work quietly, that is, display nothing except error messages. The exit
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status indicates whether or not any matches were found.
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</P>
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<P>
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<b>-r</b>, <b>--recursive</b>
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If any given path is a directory, recursively scan the files it contains,
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taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a
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directory is read as a normal file; in some operating systems this gives an
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immediate end-of-file. This option is a shorthand for setting the <b>-d</b>
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option to "recurse".
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</P>
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<P>
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<b>-s</b>, <b>--no-messages</b>
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Suppress error messages about non-existent or unreadable files. Such files are
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quietly skipped. However, the return code is still 2, even if matches were
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found in other files.
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</P>
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<P>
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<b>-u</b>, <b>--utf-8</b>
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Operate in UTF-8 mode. This option is available only if PCRE has been compiled
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with UTF-8 support. Both patterns and subject lines must be valid strings of
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UTF-8 characters.
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</P>
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<P>
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<b>-V</b>, <b>--version</b>
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Write the version numbers of <b>pcregrep</b> and the PCRE library that is being
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used to the standard error stream.
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</P>
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<P>
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<b>-v</b>, <b>--invert-match</b>
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Invert the sense of the match, so that lines which do <i>not</i> match any of
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the patterns are the ones that are found.
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</P>
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<P>
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<b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b>
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Force the patterns to match only whole words. This is equivalent to having \b
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at the start and end of the pattern.
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</P>
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<P>
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<b>-x</b>, <b>--line-regex</b>, \fP--line-regexp\fP
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Force the patterns to be anchored (each must start matching at the beginning of
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a line) and in addition, require them to match entire lines. This is
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equivalent to having ^ and $ characters at the start and end of each
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alternative branch in every pattern.
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</P>
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<br><a name="SEC4" href="#TOC1">ENVIRONMENT VARIABLES</a><br>
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<P>
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The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that
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order, for a locale. The first one that is set is used. This can be overridden
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by the <b>--locale</b> option. If no locale is set, the PCRE library's default
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(usually the "C" locale) is used.
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</P>
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<br><a name="SEC5" href="#TOC1">NEWLINES</a><br>
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<P>
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The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with
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different newline conventions from the default. However, the setting of this
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option does not affect the way in which <b>pcregrep</b> writes information to
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the standard error and output streams. It uses the string "\n" in C
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<b>printf()</b> calls to indicate newlines, relying on the C I/O library to
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convert this to an appropriate sequence if the output is sent to a file.
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</P>
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<br><a name="SEC6" href="#TOC1">OPTIONS COMPATIBILITY</a><br>
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<P>
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The majority of short and long forms of <b>pcregrep</b>'s options are the same
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as in the GNU <b>grep</b> program. Any long option of the form
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<b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b>
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(PCRE terminology). However, the <b>--locale</b>, <b>-M</b>, <b>--multiline</b>,
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<b>-u</b>, and <b>--utf-8</b> options are specific to <b>pcregrep</b>.
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</P>
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<br><a name="SEC7" href="#TOC1">OPTIONS WITH DATA</a><br>
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<P>
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There are four different ways in which an option with data can be specified.
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If a short form option is used, the data may follow immediately, or in the next
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command line item. For example:
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<pre>
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-f/some/file
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-f /some/file
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</pre>
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If a long form option is used, the data may appear in the same command line
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item, separated by an equals character, or (with one exception) it may appear
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in the next command line item. For example:
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<pre>
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--file=/some/file
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--file /some/file
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</pre>
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|
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 exception to the above is the <b>--colour</b> (or <b>--color</b>) option,
|
|
for which the data is optional. If this option does have data, it must be given
|
|
in the first form, using an equals character. Otherwise it will be assumed that
|
|
it has no data.
|
|
</P>
|
|
<br><a name="SEC8" 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 PCRE matching function has a resource limit that causes it to abort
|
|
in these circumstances. If this happens, <b>pcregrep</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>pcregrep</b> gives up.
|
|
</P>
|
|
<br><a name="SEC9" 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 and non-existent or inacessible 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 inaccessble files does not affect the return
|
|
code.
|
|
</P>
|
|
<br><a name="SEC10" href="#TOC1">AUTHOR</a><br>
|
|
<P>
|
|
Philip Hazel
|
|
<br>
|
|
University Computing Service
|
|
<br>
|
|
Cambridge CB2 3QG, England.
|
|
</P>
|
|
<P>
|
|
Last updated: 06 June 2006
|
|
<br>
|
|
Copyright © 1997-2006 University of Cambridge.
|
|
<p>
|
|
Return to the <a href="index.html">PCRE index page</a>.
|
|
</p>
|