diff -r 000000000000 -r 7f656887cf89 libraries/spcre/libpcre/pcre/doc/pcregrep.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libraries/spcre/libpcre/pcre/doc/pcregrep.1 Wed Jun 23 15:52:26 2010 +0100 @@ -0,0 +1,463 @@ +.TH PCREGREP 1 +.SH NAME +pcregrep - a grep with Perl-compatible regular expressions. +.SH SYNOPSIS +.B pcregrep [options] [long options] [pattern] [path1 path2 ...] +. +.SH DESCRIPTION +.rs +.sp +\fBpcregrep\fP searches files for character patterns, in the same way as other +grep commands do, but it uses the PCRE regular expression library to support +patterns that are compatible with the regular expressions of Perl 5. See +.\" HREF +\fBpcrepattern\fP(3) +.\" +for a full description of syntax and semantics of the regular expressions +that PCRE supports. +.P +Patterns, whether supplied on the command line or in a separate file, are given +without delimiters. For example: +.sp + pcregrep Thursday /etc/motd +.sp +If you attempt to use delimiters (for example, by surrounding a pattern with +slashes, as is common in Perl scripts), they are interpreted as part of the +pattern. Quotes can of course be used to delimit patterns on the command line +because they are interpreted by the shell, and indeed they are required if a +pattern contains white space or shell metacharacters. +.P +The first argument that follows any option settings is treated as the single +pattern to be matched when neither \fB-e\fP nor \fB-f\fP is present. +Conversely, when one or both of these options are used to specify patterns, all +arguments are treated as path names. At least one of \fB-e\fP, \fB-f\fP, or an +argument pattern must be provided. +.P +If no files are specified, \fBpcregrep\fP reads the standard input. The +standard input can also be referenced by a name consisting of a single hyphen. +For example: +.sp + pcregrep some-pattern /file1 - /file3 +.sp +By default, each line that matches a pattern is copied to the standard +output, and if there is more than one file, the file name is output at the +start of each line, followed by a colon. However, there are options that can +change how \fBpcregrep\fP behaves. In particular, the \fB-M\fP option makes it +possible to search for patterns that span line boundaries. What defines a line +boundary is controlled by the \fB-N\fP (\fB--newline\fP) option. +.P +Patterns are limited to 8K or BUFSIZ characters, whichever is the greater. +BUFSIZ is defined in \fB\fP. When there is more than one pattern +(specified by the use of \fB-e\fP and/or \fB-f\fP), each pattern is applied to +each line in the order in which they are defined, except that all the \fB-e\fP +patterns are tried before the \fB-f\fP patterns. As soon as one pattern matches +(or fails to match when \fB-v\fP is used), no further patterns are considered. +.P +When \fB--only-matching\fP, \fB--file-offsets\fP, or \fB--line-offsets\fP +is used, the output is the part of the line that matched (either shown +literally, or as an offset). In this case, scanning resumes immediately +following the match, so that further matches on the same line can be found. +If there are multiple patterns, they are all tried on the remainder of the +line. However, patterns that follow the one that matched are not tried on the +earlier part of the line. +.P +If the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variable is set, +\fBpcregrep\fP uses the value to set a locale when calling the PCRE library. +The \fB--locale\fP option can be used to override this. +. +.SH "SUPPORT FOR COMPRESSED FILES" +.rs +.sp +It is possible to compile \fBpcregrep\fP so that it uses \fBlibz\fP or +\fBlibbz2\fP to read files whose names end in \fB.gz\fP or \fB.bz2\fP, +respectively. You can find out whether your binary has support for one or both +of these file types by running it with the \fB--help\fP option. If the +appropriate support is not present, files are treated as plain text. The +standard input is always so treated. +. +.SH OPTIONS +.rs +.TP 10 +\fB--\fP +This terminate the list of options. It is useful if the next item on the +command line starts with a hyphen but is not an option. This allows for the +processing of patterns and filenames that start with hyphens. +.TP +\fB-A\fP \fInumber\fP, \fB--after-context=\fP\fInumber\fP +Output \fInumber\fP lines of context after each matching line. If filenames +and/or line numbers are being output, a hyphen separator is used instead of a +colon for the context lines. A line containing "--" is output between each +group of lines, unless they are in fact contiguous in the input file. The value +of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP +guarantees to have up to 8K of following text available for context output. +.TP +\fB-B\fP \fInumber\fP, \fB--before-context=\fP\fInumber\fP +Output \fInumber\fP lines of context before each matching line. If filenames +and/or line numbers are being output, a hyphen separator is used instead of a +colon for the context lines. A line containing "--" is output between each +group of lines, unless they are in fact contiguous in the input file. The value +of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP +guarantees to have up to 8K of preceding text available for context output. +.TP +\fB-C\fP \fInumber\fP, \fB--context=\fP\fInumber\fP +Output \fInumber\fP lines of context both before and after each matching line. +This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value. +.TP +\fB-c\fP, \fB--count\fP +Do not output individual lines; instead just output a count of the number of +lines that would otherwise have been output. If several files are given, a +count is output for each of them. In this mode, the \fB-A\fP, \fB-B\fP, and +\fB-C\fP options are ignored. +.TP +\fB--colour\fP, \fB--color\fP +If this option is given without any data, it is equivalent to "--colour=auto". +If data is required, it must be given in the same shell item, separated by an +equals sign. +.TP +\fB--colour=\fP\fIvalue\fP, \fB--color=\fP\fIvalue\fP +This option specifies under what circumstances the part of a line that matched +a pattern should be coloured in the output. The value may be "never" (the +default), "always", or "auto". In the latter case, colouring happens only if +the standard output is connected to a terminal. The colour can be specified by +setting the environment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value +of this variable should be a string of two numbers, separated by a semicolon. +They are copied directly into the control string for setting colour on a +terminal, so it is your responsibility to ensure that they make sense. If +neither of the environment variables is set, the default is "1;31", which gives +red. +.TP +\fB-D\fP \fIaction\fP, \fB--devices=\fP\fIaction\fP +If an input path is not a regular file or a directory, "action" specifies how +it is to be processed. Valid values are "read" (the default) or "skip" +(silently skip the path). +.TP +\fB-d\fP \fIaction\fP, \fB--directories=\fP\fIaction\fP +If an input path is a directory, "action" specifies how it is to be processed. +Valid values are "read" (the default), "recurse" (equivalent to the \fB-r\fP +option), or "skip" (silently skip the path). In the default case, directories +are read as if they were ordinary files. In some operating systems the effect +of reading a directory like this is an immediate end-of-file. +.TP +\fB-e\fP \fIpattern\fP, \fB--regex=\fP\fIpattern\fP, \fB--regexp=\fP\fIpattern\fP +Specify a pattern to be matched. This option can be used multiple times in +order to specify several patterns. It can also be used as a way of specifying a +single pattern that starts with a hyphen. When \fB-e\fP is used, no argument +pattern is taken from the command line; all arguments are treated as file +names. There is an overall maximum of 100 patterns. They are applied to each +line in the order in which they are defined until one matches (or fails to +match if \fB-v\fP is used). If \fB-f\fP is used with \fB-e\fP, the command line +patterns are matched first, followed by the patterns from the file, independent +of the order in which these options are specified. Note that multiple use of +\fB-e\fP is not the same as a single pattern with alternatives. For example, +X|Y finds the first character in a line that is X or Y, whereas if the two +patterns are given separately, \fBpcregrep\fP finds X if it is present, even if +it follows Y in the line. It finds Y only if there is no X in the line. This +really matters only if you are using \fB-o\fP to show the part(s) of the line +that matched. +.TP +\fB--exclude\fP=\fIpattern\fP +When \fBpcregrep\fP is searching the files in a directory as a consequence of +the \fB-r\fP (recursive search) option, any regular files whose names match the +pattern are excluded. Subdirectories are not excluded by this option; they are +searched recursively, subject to the \fB--exclude_dir\fP and +\fB--include_dir\fP options. The pattern is a PCRE regular expression, and is +matched against the final component of the file name (not the entire path). If +a file name matches both \fB--include\fP and \fB--exclude\fP, it is excluded. +There is no short form for this option. +.TP +\fB--exclude_dir\fP=\fIpattern\fP +When \fBpcregrep\fP is searching the contents of a directory as a consequence +of the \fB-r\fP (recursive search) option, any subdirectories whose names match +the pattern are excluded. (Note that the \fP--exclude\fP option does not affect +subdirectories.) The pattern is a PCRE regular expression, and is matched +against the final component of the name (not the entire path). If a +subdirectory name matches both \fB--include_dir\fP and \fB--exclude_dir\fP, it +is excluded. There is no short form for this option. +.TP +\fB-F\fP, \fB--fixed-strings\fP +Interpret each pattern as a list of fixed strings, separated by newlines, +instead of as a regular expression. The \fB-w\fP (match as a word) and \fB-x\fP +(match whole line) options can be used with \fB-F\fP. They apply to each of the +fixed strings. A line is selected if any of the fixed strings are found in it +(subject to \fB-w\fP or \fB-x\fP, if present). +.TP +\fB-f\fP \fIfilename\fP, \fB--file=\fP\fIfilename\fP +Read a number of patterns from the file, one per line, and match them against +each line of input. A data line is output if any of the patterns match it. The +filename can be given as "-" to refer to the standard input. When \fB-f\fP is +used, patterns specified on the command line using \fB-e\fP may also be +present; they are tested before the file's patterns. However, no other pattern +is taken from the command line; all arguments are treated as file names. There +is an overall maximum of 100 patterns. Trailing white space is removed from +each line, and blank lines are ignored. An empty file contains no patterns and +therefore matches nothing. See also the comments about multiple patterns versus +a single pattern with alternatives in the description of \fB-e\fP above. +.TP +\fB--file-offsets\fP +Instead of showing lines or parts of lines that match, show each match as an +offset from the start of the file and a length, separated by a comma. In this +mode, no context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP +options are ignored. If there is more than one match in a line, each of them is +shown separately. This option is mutually exclusive with \fB--line-offsets\fP +and \fB--only-matching\fP. +.TP +\fB-H\fP, \fB--with-filename\fP +Force the inclusion of the filename at the start of output lines when searching +a single file. By default, the filename is not shown in this case. For matching +lines, the filename is followed by a colon and a space; for context lines, a +hyphen separator is used. If a line number is also being output, it follows the +file name without a space. +.TP +\fB-h\fP, \fB--no-filename\fP +Suppress the output filenames when searching multiple files. By default, +filenames are shown when multiple files are searched. For matching lines, the +filename is followed by a colon and a space; for context lines, a hyphen +separator is used. If a line number is also being output, it follows the file +name without a space. +.TP +\fB--help\fP +Output a help message, giving brief details of the command options and file +type support, and then exit. +.TP +\fB-i\fP, \fB--ignore-case\fP +Ignore upper/lower case distinctions during comparisons. +.TP +\fB--include\fP=\fIpattern\fP +When \fBpcregrep\fP is searching the files in a directory as a consequence of +the \fB-r\fP (recursive search) option, only those regular files whose names +match the pattern are included. Subdirectories are always included and searched +recursively, subject to the \fP--include_dir\fP and \fB--exclude_dir\fP +options. The pattern is a PCRE regular expression, and is matched against the +final component of the file name (not the entire path). If a file name matches +both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short +form for this option. +.TP +\fB--include_dir\fP=\fIpattern\fP +When \fBpcregrep\fP is searching the contents of a directory as a consequence +of the \fB-r\fP (recursive search) option, only those subdirectories whose +names match the pattern are included. (Note that the \fB--include\fP option +does not affect subdirectories.) The pattern is a PCRE regular expression, and +is matched against the final component of the name (not the entire path). If a +subdirectory name matches both \fB--include_dir\fP and \fB--exclude_dir\fP, it +is excluded. There is no short form for this option. +.TP +\fB-L\fP, \fB--files-without-match\fP +Instead of outputting lines from the files, just output the names of the files +that do not contain any lines that would have been output. Each file name is +output once, on a separate line. +.TP +\fB-l\fP, \fB--files-with-matches\fP +Instead of outputting lines from the files, just output the names of the files +containing lines that would have been output. Each file name is output +once, on a separate line. Searching stops as soon as a matching line is found +in a file. +.TP +\fB--label\fP=\fIname\fP +This option supplies a name to be used for the standard input when file names +are being output. If not supplied, "(standard input)" is used. There is no +short form for this option. +.TP +\fB--line-offsets\fP +Instead of showing lines or parts of lines that match, show each match as a +line number, the offset from the start of the line, and a length. The line +number is terminated by a colon (as usual; see the \fB-n\fP option), and the +offset and length are separated by a comma. In this mode, no context is shown. +That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are ignored. If there is +more than one match in a line, each of them is shown separately. This option is +mutually exclusive with \fB--file-offsets\fP and \fB--only-matching\fP. +.TP +\fB--locale\fP=\fIlocale-name\fP +This option specifies a locale to be used for pattern matching. It overrides +the value in the \fBLC_ALL\fP or \fBLC_CTYPE\fP environment variables. If no +locale is specified, the PCRE library's default (usually the "C" locale) is +used. There is no short form for this option. +.TP +\fB-M\fP, \fB--multiline\fP +Allow patterns to match more than one line. When this option is given, patterns +may usefully contain literal newline characters and internal occurrences of ^ +and $ characters. The output for any one match may consist of more than one +line. When this option is set, the PCRE library is called in "multiline" mode. +There is a limit to the number of lines that can be matched, imposed by the way +that \fBpcregrep\fP buffers the input file as it scans it. However, +\fBpcregrep\fP ensures that at least 8K characters or the rest of the document +(whichever is the shorter) are available for forward matching, and similarly +the previous 8K characters (or all the previous characters, if fewer than 8K) +are guaranteed to be available for lookbehind assertions. +.TP +\fB-N\fP \fInewline-type\fP, \fB--newline=\fP\fInewline-type\fP +The PCRE library supports five different conventions for indicating +the ends of lines. They are the single-character sequences CR (carriage return) +and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention, +which recognizes any of the preceding three types, and an "any" convention, in +which any Unicode line ending sequence is assumed to end a line. The Unicode +sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF +(formfeed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and +PS (paragraph separator, U+2029). +.sp +When the PCRE library is built, a default line-ending sequence is specified. +This is normally the standard sequence for the operating system. Unless +otherwise specified by this option, \fBpcregrep\fP uses the library's default. +The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This +makes it possible to use \fBpcregrep\fP on files that have come from other +environments without having to modify their line endings. If the data that is +being scanned does not agree with the convention set by this option, +\fBpcregrep\fP may behave in strange ways. +.TP +\fB-n\fP, \fB--line-number\fP +Precede each output line by its line number in the file, followed by a colon +and a space for matching lines or a hyphen and a space for context lines. If +the filename is also being output, it precedes the line number. This option is +forced if \fB--line-offsets\fP is used. +.TP +\fB-o\fP, \fB--only-matching\fP +Show only the part of the line that matched a pattern. In this mode, no +context is shown. That is, the \fB-A\fP, \fB-B\fP, and \fB-C\fP options are +ignored. If there is more than one match in a line, each of them is shown +separately. If \fB-o\fP is combined with \fB-v\fP (invert the sense of the +match to find non-matching lines), no output is generated, but the return code +is set appropriately. This option is mutually exclusive with +\fB--file-offsets\fP and \fB--line-offsets\fP. +.TP +\fB-q\fP, \fB--quiet\fP +Work quietly, that is, display nothing except error messages. The exit +status indicates whether or not any matches were found. +.TP +\fB-r\fP, \fB--recursive\fP +If any given path is a directory, recursively scan the files it contains, +taking note of any \fB--include\fP and \fB--exclude\fP settings. By default, a +directory is read as a normal file; in some operating systems this gives an +immediate end-of-file. This option is a shorthand for setting the \fB-d\fP +option to "recurse". +.TP +\fB-s\fP, \fB--no-messages\fP +Suppress error messages about non-existent or unreadable files. Such files are +quietly skipped. However, the return code is still 2, even if matches were +found in other files. +.TP +\fB-u\fP, \fB--utf-8\fP +Operate in UTF-8 mode. This option is available only if PCRE has been compiled +with UTF-8 support. Both patterns and subject lines must be valid strings of +UTF-8 characters. +.TP +\fB-V\fP, \fB--version\fP +Write the version numbers of \fBpcregrep\fP and the PCRE library that is being +used to the standard error stream. +.TP +\fB-v\fP, \fB--invert-match\fP +Invert the sense of the match, so that lines which do \fInot\fP match any of +the patterns are the ones that are found. +.TP +\fB-w\fP, \fB--word-regex\fP, \fB--word-regexp\fP +Force the patterns to match only whole words. This is equivalent to having \eb +at the start and end of the pattern. +.TP +\fB-x\fP, \fB--line-regex\fP, \fB--line-regexp\fP +Force the patterns to be anchored (each must start matching at the beginning of +a line) and in addition, require them to match entire lines. This is +equivalent to having ^ and $ characters at the start and end of each +alternative branch in every pattern. +. +. +.SH "ENVIRONMENT VARIABLES" +.rs +.sp +The environment variables \fBLC_ALL\fP and \fBLC_CTYPE\fP are examined, in that +order, for a locale. The first one that is set is used. This can be overridden +by the \fB--locale\fP option. If no locale is set, the PCRE library's default +(usually the "C" locale) is used. +. +. +.SH "NEWLINES" +.rs +.sp +The \fB-N\fP (\fB--newline\fP) option allows \fBpcregrep\fP to scan files with +different newline conventions from the default. However, the setting of this +option does not affect the way in which \fBpcregrep\fP writes information to +the standard error and output streams. It uses the string "\en" in C +\fBprintf()\fP calls to indicate newlines, relying on the C I/O library to +convert this to an appropriate sequence if the output is sent to a file. +. +. +.SH "OPTIONS COMPATIBILITY" +.rs +.sp +The majority of short and long forms of \fBpcregrep\fP's options are the same +as in the GNU \fBgrep\fP program. Any long option of the form +\fB--xxx-regexp\fP (GNU terminology) is also available as \fB--xxx-regex\fP +(PCRE terminology). However, the \fB--locale\fP, \fB-M\fP, \fB--multiline\fP, +\fB-u\fP, and \fB--utf-8\fP options are specific to \fBpcregrep\fP. +. +. +.SH "OPTIONS WITH DATA" +.rs +.sp +There are four different ways in which an option with data can be specified. +If a short form option is used, the data may follow immediately, or in the next +command line item. For example: +.sp + -f/some/file + -f /some/file +.sp +If a long form option is used, the data may appear in the same command line +item, separated by an equals character, or (with one exception) it may appear +in the next command line item. For example: +.sp + --file=/some/file + --file /some/file +.sp +Note, however, that if you want to supply a file name beginning with ~ as data +in a shell command, and have the shell expand ~ to a home directory, you must +separate the file name from the option, because the shell does not treat ~ +specially unless it is at the start of an item. +.P +The exception to the above is the \fB--colour\fP (or \fB--color\fP) 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. +. +. +.SH "MATCHING ERRORS" +.rs +.sp +It is possible to supply a regular expression that takes a very long time to +fail to match certain lines. Such patterns normally involve nested indefinite +repeats, for example: (a+)*\ed when matched against a line of a's with no final +digit. The PCRE matching function has a resource limit that causes it to abort +in these circumstances. If this happens, \fBpcregrep\fP outputs an error +message and the line that caused the problem to the standard error stream. If +there are more than 20 such errors, \fBpcregrep\fP gives up. +. +. +.SH DIAGNOSTICS +.rs +.sp +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 \fB-s\fP option to +suppress error messages about inaccessble files does not affect the return +code. +. +. +.SH "SEE ALSO" +.rs +.sp +\fBpcrepattern\fP(3), \fBpcretest\fP(1). +. +. +.SH AUTHOR +.rs +.sp +.nf +Philip Hazel +University Computing Service +Cambridge CB2 3QH, England. +.fi +. +. +.SH REVISION +.rs +.sp +.nf +Last updated: 08 March 2008 +Copyright (c) 1997-2008 University of Cambridge. +.fi