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Diffstat (limited to 'doc/pcregrep.txt')
| -rw-r--r-- | doc/pcregrep.txt | 232 |
1 files changed, 116 insertions, 116 deletions
diff --git a/doc/pcregrep.txt b/doc/pcregrep.txt index 97d9a7b..0c873c7 100644 --- a/doc/pcregrep.txt +++ b/doc/pcregrep.txt @@ -26,8 +26,8 @@ DESCRIPTION If you attempt to use delimiters (for example, by surrounding a pattern with slashes, as is common in Perl scripts), they are interpreted as part of the pattern. Quotes can of course be used to delimit patterns - on the command line because they are interpreted by the shell, and - indeed quotes are required if a pattern contains white space or shell + on the command line because they are interpreted by the shell, and in- + deed quotes are required if a pattern contains white space or shell metacharacters. The first argument that follows any option settings is treated as the @@ -37,8 +37,8 @@ DESCRIPTION or an argument pattern must be provided. If no files are specified, pcregrep reads the standard input. The stan- - dard input can also be referenced by a name consisting of a single - hyphen. For example: + dard input can also be referenced by a name consisting of a single hy- + phen. For example: pcregrep some-pattern /file1 - /file3 @@ -47,8 +47,8 @@ DESCRIPTION the start of each line, followed by a colon. However, there are options that can change how pcregrep behaves. In particular, the -M option makes it possible to search for patterns that span line boundaries. - What defines a line boundary is controlled by the -N (--newline) - option. + What defines a line boundary is controlled by the -N (--newline) op- + tion. 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. @@ -66,12 +66,12 @@ DESCRIPTION By default, as soon as one pattern matches a line, no further patterns are considered. However, if --colour (or --color) is used to colour the matching substrings, or if --only-matching, --file-offsets, or --line- - offsets is used to output only the part of the line that matched - (either shown literally, or as an offset), scanning resumes immediately + offsets is used to output only the part of the line that matched (ei- + ther shown literally, or as an offset), scanning resumes immediately following the match, so that further matches on the same line can be - found. If there are multiple patterns, they are all tried on the - remainder of the line, but patterns that follow the one that matched - are not tried on the earlier part of the line. + found. If there are multiple patterns, they are all tried on the re- + mainder of the line, but patterns that follow the one that matched are + not tried on the earlier part of the line. This behaviour means that the order in which multiple patterns are specified can affect the output when one of the above options is used. @@ -80,11 +80,11 @@ DESCRIPTION overlap). Patterns that can match an empty string are accepted, but empty string - matches are never recognized. An example is the pattern - "(super)?(man)?", in which all components are optional. This pattern - finds all occurrences of both "super" and "man"; the output differs - from matching with "super|man" when only the matching substrings are - being shown. + matches are never recognized. An example is the pattern "(su- + per)?(man)?", in which all components are optional. This pattern finds + all occurrences of both "super" and "man"; the output differs from + matching with "super|man" when only the matching substrings are being + shown. If the LC_ALL or LC_CTYPE environment variable is set, pcregrep uses the value to set a locale when calling the PCRE library. The --locale @@ -105,9 +105,9 @@ BINARY FILES By default, a file that contains a binary zero byte within the first 1024 bytes is identified as a binary file, and is processed specially. - (GNU grep also identifies binary files in this manner.) See the - --binary-files option for a means of changing the way binary files are - handled. + (GNU grep also identifies binary files in this manner.) See the --bi- + nary-files option for a means of changing the way binary files are han- + dled. OPTIONS @@ -151,16 +151,16 @@ OPTIONS --binary-files=word Specify how binary files are to be processed. If the word is - "binary" (the default), pattern matching is performed on - binary files, but the only output is "Binary file <name> + "binary" (the default), pattern matching is performed on bi- + nary files, but the only output is "Binary file <name> matches" when a match succeeds. If the word is "text", which is equivalent to the -a or --text option, binary files are processed in the same way as any other file. In this case, when a match succeeds, the output may be binary garbage, which can have nasty effects if sent to a terminal. If the - word is "without-match", which is equivalent to the -I - option, binary files are not processed at all; they are - assumed not to be of interest. + word is "without-match", which is equivalent to the -I op- + tion, binary files are not processed at all; they are assumed + not to be of interest. --buffer-size=number Set the parameter that controls how much memory is used for @@ -201,15 +201,15 @@ OPTIONS ronment 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 + string for setting colour on a terminal, so it is your re- + sponsibility to ensure that they make sense. If neither of the environment variables is set, the default is "1;31", which gives red. -D action, --devices=action - If an input path is not a regular file or a directory, - "action" specifies how it is to be processed. Valid values - are "read" (the default) or "skip" (silently skip the path). + If an input path is not a regular file or a directory, "ac- + tion" specifies how it is to be processed. Valid values are + "read" (the default) or "skip" (silently skip the path). -d action, --directories=action If an input path is a directory, "action" specifies how it is @@ -218,8 +218,8 @@ OPTIONS "recurse" (equivalent to the -r option), or "skip" (silently skip the path, the default in Windows environments). In the "read" case, directories are read as if they were ordinary - files. In some operating systems the effect of reading a - directory like this is an immediate end-of-file; in others it + files. In some operating systems the effect of reading a di- + rectory like this is an immediate end-of-file; in others it may provoke an error. -e pattern, --regex=pattern, --regexp=pattern @@ -249,8 +249,8 @@ OPTIONS whether listed on the command line, obtained from --file- list, or by scanning a directory. The pattern is a PCRE regu- lar expression, and is matched against the final component of - the file name, not the entire path. The -F, -w, and -x - options do not apply to this pattern. The option may be given + the file name, not the entire path. The -F, -w, and -x op- + tions do not apply to this pattern. The option may be given any number of times in order to specify multiple patterns. If a file name matches both an --include and an --exclude pat- tern, it is excluded. There is no short form for this option. @@ -264,29 +264,29 @@ OPTIONS --exclude-dir=pattern Directories whose names match the pattern are skipped without - being processed, whatever the setting of the --recursive - option. This applies to all directories, whether listed on - the command line, obtained from --file-list, or by scanning a + being processed, whatever the setting of the --recursive op- + tion. This applies to all directories, whether listed on the + command line, obtained from --file-list, or by scanning a parent directory. The pattern is a PCRE regular expression, and is matched against the final component of the directory name, not the entire path. The -F, -w, and -x options do not apply to this pattern. The option may be given any number of times in order to specify more than one pattern. If a direc- - tory matches both --include-dir and --exclude-dir, it is - excluded. There is no short form for this option. + tory matches both --include-dir and --exclude-dir, it is ex- + cluded. There is no short form for this option. -F, --fixed-strings Interpret each data-matching pattern as a list of fixed - strings, separated by newlines, instead of as a regular - expression. What constitutes a newline for this purpose is - controlled by the --newline option. The -w (match as a word) - and -x (match whole line) options can be used with -F. They - apply to each of the fixed strings. A line is selected if any + strings, separated by newlines, instead of as a regular ex- + pression. What constitutes a newline for this purpose is con- + trolled by the --newline option. The -w (match as a word) and + -x (match whole line) options can be used with -F. They ap- + ply to each of the fixed strings. A line is selected if any of the fixed strings are found in it (subject to -w or -x, if present). This option applies only to the patterns that are matched against the contents of files; it does not apply to - patterns specified by any of the --include or --exclude - options. + patterns specified by any of the --include or --exclude op- + tions. -f filename, --file=filename Read patterns from the file, one per line, and match them @@ -358,16 +358,16 @@ OPTIONS --include=pattern If any --include patterns are specified, the only files that are processed are those that match one of the patterns (and - do not match an --exclude pattern). This option does not - affect directories, but it applies to all files, whether - listed on the command line, obtained from --file-list, or by - scanning a directory. The pattern is a PCRE regular expres- - sion, and is matched against the final component of the file - name, not the entire path. The -F, -w, and -x options do not - apply to this pattern. The option may be given any number of - times. If a file name matches both an --include and an - --exclude pattern, it is excluded. There is no short form - for this option. + do not match an --exclude pattern). This option does not af- + fect directories, but it applies to all files, whether listed + on the command line, obtained from --file-list, or by scan- + ning a directory. The pattern is a PCRE regular expression, + and is matched against the final component of the file name, + not the entire path. The -F, -w, and -x options do not apply + to this pattern. The option may be given any number of times. + If a file name matches both an --include and an --exclude + pattern, it is excluded. There is no short form for this op- + tion. --include-from=filename Treat each non-empty line of the file as the data for an @@ -381,8 +381,8 @@ OPTIONS tories that are processed are those that match one of the patterns (and do not match an --exclude-dir pattern). This applies to all directories, whether listed on the command - line, obtained from --file-list, or by scanning a parent - directory. The pattern is a PCRE regular expression, and is + line, obtained from --file-list, or by scanning a parent di- + rectory. The pattern is a PCRE regular expression, and is matched against the final component of the directory name, not the entire path. The -F, -w, and -x options do not apply to this pattern. The option may be given any number of times. @@ -413,9 +413,9 @@ OPTIONS --line-buffered When this option is given, input is read and processed line - by line, and the output is flushed after each write. By - default, input is read in large chunks, unless pcregrep can - determine that it is reading from a terminal (which is cur- + by line, and the output is flushed after each write. By de- + fault, input is read in large chunks, unless pcregrep can de- + termine that it is reading from a terminal (which is cur- rently possible only in Unix-like environments). Output to terminal is normally automatically flushed by the operating system. This option can be useful when the input or output is @@ -437,9 +437,9 @@ OPTIONS --locale=locale-name This option specifies a locale to be used for pattern match- ing. It overrides the value in the LC_ALL or LC_CTYPE envi- - ronment variables. If no locale is specified, the PCRE - library's default (usually the "C" locale) is used. There is - no short form for this option. + ronment variables. If no locale is specified, the PCRE li- + brary's default (usually the "C" locale) is used. There is no + short form for this option. --match-limit=number Processing some regular expression patterns can require a @@ -447,26 +447,26 @@ OPTIONS gram crash if not enough is available. Other patterns may take a very long time to search for all possible matching strings. The pcre_exec() function that is called by pcregrep - to do the matching has two parameters that can limit the - resources that it uses. + to do the matching has two parameters that can limit the re- + sources that it uses. - The --match-limit option provides a means of limiting - resource usage when processing patterns that are not going to + The --match-limit option provides a means of limiting re- + source usage when processing patterns that are not going to match, but which have a very large number of possibilities in their search trees. The classic example is a pattern that uses nested unlimited repeats. Internally, PCRE uses a func- - tion called match() which it calls repeatedly (sometimes - recursively). The limit set by --match-limit is imposed on - the number of times this function is called during a match, - which has the effect of limiting the amount of backtracking - that can take place. + tion called match() which it calls repeatedly (sometimes re- + cursively). The limit set by --match-limit is imposed on the + number of times this function is called during a match, which + has the effect of limiting the amount of backtracking that + can take place. The --recursion-limit option is similar to --match-limit, but instead of limiting the total number of times that match() is called, it limits the depth of recursive calls, which in turn limits the amount of memory that can be used. The recursion - depth is a smaller number than the total number of calls, - because not all calls to match() are recursive. This limit is + depth is a smaller number than the total number of calls, be- + cause not all calls to match() are recursive. This limit is of use only if it is set smaller than --match-limit. There are no short forms for these options. The default set- @@ -494,30 +494,30 @@ OPTIONS is read line by line (see --line-buffered.) -N newline-type, --newline=newline-type - 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 rec- - ognizes any of the preceding three types, and an "any" con- - vention, in which any Unicode line ending sequence is assumed - to end a line. The Unicode sequences are the three just men- + The PCRE library supports five different conventions for in- + dicating the ends of lines. They are the single-character se- + quences CR (carriage return) and LF (linefeed), the two-char- + acter sequence CRLF, an "anycrlf" convention, which recog- + nizes any of the preceding three types, and an "any" conven- + tion, in which any Unicode line ending sequence is assumed to + end a line. The Unicode sequences are the three just men- tioned, plus VT (vertical tab, U+000B), FF (form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS (paragraph separator, U+2029). - When the 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, pcregrep uses the library's default. The - possible values for this option are CR, LF, CRLF, ANYCRLF, or - ANY. This makes it possible to use pcregrep to scan files - that have come from other environments without having to mod- - ify their line endings. If the data that is being scanned - does not agree with the convention set by this option, pcre- - grep may behave in strange ways. Note that this option does - not apply to files specified by the -f, --exclude-from, or - --include-from options, which are expected to use the operat- - ing system's standard newline sequence. + When the PCRE library is built, a default line-ending se- + quence is specified. This is normally the standard sequence + for the operating system. Unless otherwise specified by this + option, pcregrep uses the library's default. The possible + values for this option are CR, LF, CRLF, ANYCRLF, or ANY. + This makes it possible to use pcregrep to scan files that + have come from other environments without having to modify + their line endings. If the data that is being scanned does + not agree with the convention set by this option, pcregrep + may behave in strange ways. Note that this option does not + apply to files specified by the -f, --exclude-from, or --in- + clude-from options, which are expected to use the operating + system's standard newline sequence. -n, --line-number Precede each output line by its line number in the file, fol- @@ -538,12 +538,12 @@ OPTIONS is, the -A, -B, and -C options are ignored. If there is more than one match in a line, each of them is shown separately. If -o is combined with -v (invert the sense of the match to - find non-matching lines), no output is generated, but the - return code is set appropriately. If the matched portion of - the line is empty, nothing is output unless the file name or - line number are being printed, in which case they are shown - on an otherwise empty line. This option is mutually exclusive - with --file-offsets and --line-offsets. + find non-matching lines), no output is generated, but the re- + turn code is set appropriately. If the matched portion of the + line is empty, nothing is output unless the file name or line + number are being printed, in which case they are shown on an + otherwise empty line. This option is mutually exclusive with + --file-offsets and --line-offsets. -onumber, --only-matching=number Show only the part of the line that matched the capturing @@ -579,8 +579,8 @@ OPTIONS it contains, taking note of any --include and --exclude set- tings. By default, a directory is read as a normal file; in some operating systems this gives an immediate end-of-file. - This option is a shorthand for setting the -d option to - "recurse". + This option is a shorthand for setting the -d option to "re- + curse". --recursion-limit=number See --match-limit above. @@ -626,10 +626,10 @@ OPTIONS ENVIRONMENT VARIABLES - The environment variables LC_ALL and LC_CTYPE are examined, in that - order, for a locale. The first one that is set is used. This can be - overridden by the --locale option. If no locale is set, the PCRE - library's default (usually the "C" locale) is used. + The environment variables LC_ALL and LC_CTYPE are examined, in that or- + der, for a locale. The first one that is set is used. This can be over- + ridden by the --locale option. If no locale is set, the PCRE library's + default (usually the "C" locale) is used. NEWLINES @@ -640,8 +640,8 @@ NEWLINES ever newline sequences they have in the input. However, the setting of this option does not affect the interpretation of files specified by the -f, --exclude-from, or --include-from options, which are assumed to - use the operating system's standard newline sequence, nor does it - affect the way in which pcregrep writes informational messages to the + use the operating system's standard newline sequence, nor does it af- + fect the way in which pcregrep writes informational messages to the standard error and output streams. For these it uses the string "\n" to indicate newlines, relying on the C I/O library to convert this to an appropriate sequence. @@ -687,13 +687,13 @@ OPTIONS WITH DATA --file /some/file Note, however, that if you want to supply a file name beginning with ~ - as data in a shell command, and have the shell expand ~ to a home - directory, you must separate the file name from the option, because the + as data in a shell command, and have the shell expand ~ to a home di- + rectory, you must separate the file name from the option, because the shell does not treat ~ specially unless it is at the start of an item. The exceptions to the above are the --colour (or --color) and --only- - matching options, for which the data is optional. If one of these - options does have data, it must be given in the first form, using an + matching options, for which the data is optional. If one of these op- + tions does have data, it must be given in the first form, using an equals character. Otherwise pcregrep will assume that it has no data. @@ -702,14 +702,14 @@ MATCHING ERRORS It is possible to supply a regular expression that takes a very long time to fail to match certain lines. Such patterns normally involve nested indefinite repeats, for example: (a+)*\d when matched against a - line of a's with no final digit. The PCRE matching function has a - resource limit that causes it to abort in these circumstances. If this + line of a's with no final digit. The PCRE matching function has a re- + source limit that causes it to abort in these circumstances. If this happens, pcregrep outputs an error message and the line that caused the problem to the standard error stream. If there are more than 20 such errors, pcregrep gives up. - The --match-limit option of pcregrep can be used to set the overall - resource limit; there is a second option called --recursion-limit that + The --match-limit option of pcregrep can be used to set the overall re- + source limit; there is a second option called --recursion-limit that sets a limit on the amount of memory (usually stack) that is used (see the discussion of these options above). |