| 1 | .\" GNU grep man page
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| 2 | .if !\n(.g \{\
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| 3 | . if !\w|\*(lq| \{\
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| 4 | . ds lq ``
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| 5 | . if \w'\(lq' .ds lq "\(lq
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| 6 | . \}
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| 7 | . if !\w|\*(rq| \{\
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| 8 | . ds rq ''
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| 9 | . if \w'\(rq' .ds rq "\(rq
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| 10 | . \}
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| 11 | .\}
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| 12 | .ie t .ds Tx \s-1T\v'.4n'\h'-.1667'E\v'-.4n'\h'-.125'X\s0
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| 13 | . el .ds Tx TeX
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| 14 | .de Id
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| 15 | . ds Yr \\$4
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| 16 | . substring Yr 0 3
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| 17 | . ds Mn \\$4
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| 18 | . substring Mn 5 6
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| 19 | . ds Dy \\$4
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| 20 | . substring Dy 8 9
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| 21 | . \" ISO 8601 date, complete format, extended representation
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| 22 | . ds Dt \\*(Yr-\\*(Mn-\\*(Dy
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| 23 | ..
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| 24 | .TH GREP 1 \*(Dt "GNU grep @VERSION@" "User Commands"
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| 25 | .hy 0
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| 26 | .
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| 27 | .SH NAME
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| 28 | grep, egrep, fgrep \- print lines matching a pattern
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| 29 | .
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| 30 | .SH SYNOPSIS
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| 31 | .B grep
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| 32 | .RI [ OPTIONS ]
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| 33 | .I PATTERN
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| 34 | .RI [ FILE .\|.\|.]
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| 35 | .br
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| 36 | .B grep
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| 37 | .RI [ OPTIONS ]
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| 38 | .RB [ \-e
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| 39 | .I PATTERN
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| 40 | |
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| 41 | .B \-f
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| 42 | .IR FILE ]
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| 43 | .RI [ FILE .\|.\|.]
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| 44 | .
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| 45 | .SH DESCRIPTION
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| 46 | .B grep
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| 47 | searches the named input
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| 48 | .IR FILE s
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| 49 | (or standard input if no files are named,
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| 50 | or if a single hyphen-minus
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| 51 | .RB ( \- )
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| 52 | is given as file name)
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| 53 | for lines containing a match to the given
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| 54 | .IR PATTERN .
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| 55 | By default,
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| 56 | .B grep
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| 57 | prints the matching lines.
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| 58 | .PP
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| 59 | In addition, two variant programs
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| 60 | .B egrep
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| 61 | and
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| 62 | .B fgrep
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| 63 | are available.
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| 64 | .B egrep
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| 65 | is the same as
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| 66 | .BR "grep\ \-E" .
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| 67 | .B fgrep
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| 68 | is the same as
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| 69 | .BR "grep\ \-F" .
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| 70 | Direct invocation as either
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| 71 | .B egrep
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| 72 | or
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| 73 | .B fgrep
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| 74 | is deprecated,
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| 75 | but is provided to allow historical applications
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| 76 | that rely on them to run unmodified.
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| 77 | .
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| 78 | .SH OPTIONS
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| 79 | .SS "Generic Program Information"
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| 80 | .TP
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| 81 | .B \-\^\-help
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| 82 | Print a usage message briefly summarizing these command-line options
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| 83 | and the bug-reporting address, then exit.
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| 84 | .TP
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| 85 | .BR \-V ", " \-\^\-version
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| 86 | Print the version number of
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| 87 | .B grep
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| 88 | to the standard output stream.
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| 89 | This version number should
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| 90 | be included in all bug reports (see below).
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| 91 | .SS "Matcher Selection"
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| 92 | .TP
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| 93 | .BR \-E ", " \-\^\-extended\-regexp
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| 94 | Interpret
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| 95 | .I PATTERN
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| 96 | as an extended regular expression (ERE, see below).
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| 97 | .RB ( \-E
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| 98 | is specified by \s-1POSIX\s0.)
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| 99 | .TP
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| 100 | .BR \-F ", " \-\^\-fixed\-strings
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| 101 | Interpret
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| 102 | .I PATTERN
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| 103 | as a list of fixed strings, separated by newlines,
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| 104 | any of which is to be matched.
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| 105 | .RB ( \-F
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| 106 | is specified by \s-1POSIX\s0.)
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| 107 | .TP
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| 108 | .BR \-G ", " \-\^\-basic\-regexp
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| 109 | Interpret
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| 110 | .I PATTERN
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| 111 | as a basic regular expression (BRE, see below).
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| 112 | This is the default.
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| 113 | .TP
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| 114 | .BR \-P ", " \-\^\-perl\-regexp
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| 115 | Interpret
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| 116 | .I PATTERN
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| 117 | as a Perl regular expression.
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| 118 | This is highly experimental and
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| 119 | .B "grep \-P"
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| 120 | may warn of unimplemented features.
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| 121 | .SS "Matching Control"
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| 122 | .TP
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| 123 | .BI \-e " PATTERN" "\fR,\fP \-\^\-regexp=" PATTERN
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| 124 | Use
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| 125 | .I PATTERN
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| 126 | as the pattern.
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| 127 | This can be used to specify multiple search patterns,
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| 128 | or to protect a pattern beginning with a hyphen
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| 129 | .RB ( \- ).
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| 130 | .RB ( \-e
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| 131 | is specified by \s-1POSIX\s0.)
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| 132 | .TP
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| 133 | .BI \-f " FILE" "\fR,\fP \-\^\-file=" FILE
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| 134 | Obtain patterns from
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| 135 | .IR FILE ,
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| 136 | one per line.
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| 137 | The empty file contains zero patterns, and therefore matches nothing.
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| 138 | .RB ( \-f
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| 139 | is specified by \s-1POSIX\s0.)
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| 140 | .TP
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| 141 | .BR \-i ", " \-\^\-ignore\-case
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| 142 | Ignore case distinctions in both the
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| 143 | .I PATTERN
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| 144 | and the input files.
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| 145 | .RB ( \-i
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| 146 | is specified by \s-1POSIX\s0.)
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| 147 | .TP
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| 148 | .BR \-v ", " \-\^\-invert\-match
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| 149 | Invert the sense of matching, to select non-matching lines.
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| 150 | .RB ( \-v
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| 151 | is specified by \s-1POSIX\s0.)
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| 152 | .TP
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| 153 | .BR \-w ", " \-\^\-word\-regexp
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| 154 | Select only those lines containing matches that form whole words.
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| 155 | The test is that the matching substring must either be at the
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| 156 | beginning of the line, or preceded by a non-word constituent
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| 157 | character.
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| 158 | Similarly, it must be either at the end of the line
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| 159 | or followed by a non-word constituent character.
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| 160 | Word-constituent characters are letters, digits, and the underscore.
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| 161 | .TP
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| 162 | .BR \-x ", " \-\^\-line\-regexp
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| 163 | Select only those matches that exactly match the whole line.
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| 164 | .RB ( \-x
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| 165 | is specified by \s-1POSIX\s0.)
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| 166 | .TP
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| 167 | .B \-y
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| 168 | Obsolete synonym for
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| 169 | .BR \-i .
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| 170 | .SS "General Output Control"
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| 171 | .TP
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| 172 | .BR \-c ", " \-\^\-count
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| 173 | Suppress normal output; instead print a count of
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| 174 | matching lines for each input file.
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| 175 | With the
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| 176 | .BR \-v ", " \-\^\-invert\-match
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| 177 | option (see below), count non-matching lines.
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| 178 | .RB ( \-c
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| 179 | is specified by \s-1POSIX\s0.)
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| 180 | .TP
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| 181 | .BR \-\^\-color [ =\fIWHEN\fP "], " \-\^\-colour [ =\fIWHEN\fP ]
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| 182 | Surround the matched (non-empty) strings, matching lines, context lines,
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| 183 | file names, line numbers, byte offsets, and separators (for fields and
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| 184 | groups of context lines) with escape sequences to display them in color
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| 185 | on the terminal.
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| 186 | The colors are defined by the environment variable
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| 187 | .BR GREP_COLORS .
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| 188 | The deprecated environment variable
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| 189 | .B GREP_COLOR
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| 190 | is still supported, but its setting does not have priority.
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| 191 | .I WHEN
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| 192 | is
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| 193 | .BR never ", " always ", or " auto .
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| 194 | .TP
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| 195 | .BR \-L ", " \-\^\-files\-without\-match
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| 196 | Suppress normal output; instead print the name
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| 197 | of each input file from which no output would
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| 198 | normally have been printed.
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| 199 | The scanning will stop on the first match.
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| 200 | .TP
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| 201 | .BR \-l ", " \-\^\-files\-with\-matches
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| 202 | Suppress normal output; instead print
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| 203 | the name of each input file from which output
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| 204 | would normally have been printed.
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| 205 | The scanning will stop on the first match.
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| 206 | .RB ( \-l
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| 207 | is specified by \s-1POSIX\s0.)
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| 208 | .TP
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| 209 | .BI \-m " NUM" "\fR,\fP \-\^\-max\-count=" NUM
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| 210 | Stop reading a file after
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| 211 | .I NUM
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| 212 | matching lines.
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| 213 | If the input is standard input from a regular file,
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| 214 | and
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| 215 | .I NUM
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| 216 | matching lines are output,
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| 217 | .B grep
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| 218 | ensures that the standard input is positioned to just after the last
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| 219 | matching line before exiting, regardless of the presence of trailing
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| 220 | context lines.
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| 221 | This enables a calling process to resume a search.
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| 222 | When
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| 223 | .B grep
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| 224 | stops after
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| 225 | .I NUM
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| 226 | matching lines, it outputs any trailing context lines.
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| 227 | When the
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| 228 | .B \-c
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| 229 | or
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| 230 | .B \-\^\-count
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| 231 | option is also used,
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| 232 | .B grep
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| 233 | does not output a count greater than
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| 234 | .IR NUM .
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| 235 | When the
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| 236 | .B \-v
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| 237 | or
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| 238 | .B \-\^\-invert\-match
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| 239 | option is also used,
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| 240 | .B grep
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| 241 | stops after outputting
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| 242 | .I NUM
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| 243 | non-matching lines.
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| 244 | .TP
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| 245 | .BR \-o ", " \-\^\-only\-matching
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| 246 | Print only the matched (non-empty) parts of a matching line,
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| 247 | with each such part on a separate output line.
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| 248 | .TP
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| 249 | .BR \-q ", " \-\^\-quiet ", " \-\^\-silent
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| 250 | Quiet; do not write anything to standard output.
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| 251 | Exit immediately with zero status if any match is found,
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| 252 | even if an error was detected.
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| 253 | Also see the
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| 254 | .B \-s
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| 255 | or
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| 256 | .B \-\^\-no\-messages
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| 257 | option.
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| 258 | .RB ( \-q
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| 259 | is specified by \s-1POSIX\s0.)
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| 260 | .TP
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| 261 | .BR \-s ", " \-\^\-no\-messages
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| 262 | Suppress error messages about nonexistent or unreadable files.
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| 263 | Portability note: unlike \s-1GNU\s0
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| 264 | .BR grep ,
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| 265 | 7th Edition Unix
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| 266 | .B grep
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| 267 | did not conform to \s-1POSIX\s0, because it lacked
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| 268 | .B \-q
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| 269 | and its
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| 270 | .B \-s
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| 271 | option behaved like \s-1GNU\s0
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| 272 | .BR grep 's
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| 273 | .B \-q
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| 274 | option.
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| 275 | \s-1USG\s0-style
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| 276 | .B grep
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| 277 | also lacked
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| 278 | .B \-q
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| 279 | but its
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| 280 | .B \-s
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| 281 | option behaved like \s-1GNU\s0
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| 282 | .BR grep .
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| 283 | Portable shell scripts
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| 284 | should avoid both
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| 285 | .B \-q
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| 286 | and
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| 287 | .B \-s
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| 288 | and should redirect standard and error output to
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| 289 | .B /dev/null
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| 290 | instead.
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| 291 | .RB ( \-s
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| 292 | is specified by \s-1POSIX\s0.)
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| 293 | .SS "Output Line Prefix Control"
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| 294 | .TP
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| 295 | .BR \-b ", " \-\^\-byte\-offset
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| 296 | Print the 0-based byte offset within the input file
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| 297 | before each line of output.
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| 298 | If
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| 299 | .B \-o
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| 300 | .RB ( \-\^\-only\-matching )
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| 301 | is specified,
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| 302 | print the offset of the matching part itself.
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| 303 | .TP
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| 304 | .BR \-H ", " \-\^\-with\-filename
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| 305 | Print the file name for each match.
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| 306 | This is the default when there is more than one file to search.
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| 307 | .TP
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| 308 | .BR \-h ", " \-\^\-no\-filename
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| 309 | Suppress the prefixing of file names on output.
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| 310 | This is the default when there is only one file
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| 311 | (or only standard input) to search.
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| 312 | .TP
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| 313 | .BI \-\^\-label= LABEL
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| 314 | Display input actually coming from standard input as input coming from file
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| 315 | .IR LABEL .
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| 316 | This is especially useful when implementing tools like
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| 317 | .BR zgrep ,
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| 318 | e.g.,
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| 319 | .BR "gzip -cd foo.gz | grep --label=foo -H something" .
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| 320 | See also the
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| 321 | .B \-H
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| 322 | option.
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| 323 | .TP
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| 324 | .BR \-n ", " \-\^\-line\-number
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| 325 | Prefix each line of output with the 1-based line number
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| 326 | within its input file.
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| 327 | .RB ( \-n
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| 328 | is specified by \s-1POSIX\s0.)
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| 329 | .TP
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| 330 | .BR \-T ", " \-\^\-initial\-tab
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| 331 | Make sure that the first character of actual line content lies on a
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| 332 | tab stop, so that the alignment of tabs looks normal.
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| 333 | This is useful with options that prefix their output to the actual content:
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| 334 | .BR \-H , \-n ,
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| 335 | and
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| 336 | .BR \-b .
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| 337 | In order to improve the probability that lines
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| 338 | from a single file will all start at the same column,
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| 339 | this also causes the line number and byte offset (if present)
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| 340 | to be printed in a minimum size field width.
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| 341 | .TP
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| 342 | .BR \-u ", " \-\^\-unix\-byte\-offsets
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| 343 | Report Unix-style byte offsets.
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| 344 | This switch causes
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| 345 | .B grep
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| 346 | to report byte offsets as if the file were a Unix-style text file,
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| 347 | i.e., with CR characters stripped off.
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| 348 | This will produce results identical to running
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| 349 | .B grep
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| 350 | on a Unix machine.
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| 351 | This option has no effect unless
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| 352 | .B \-b
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| 353 | option is also used;
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| 354 | it has no effect on platforms other than \s-1MS-DOS\s0 and \s-1MS\s0-Windows.
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| 355 | .TP
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| 356 | .BR \-Z ", " \-\^\-null
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| 357 | Output a zero byte (the \s-1ASCII\s0
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| 358 | .B NUL
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| 359 | character) instead of the character that normally follows a file name.
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| 360 | For example,
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| 361 | .B "grep \-lZ"
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| 362 | outputs a zero byte after each file name instead of the usual newline.
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| 363 | This option makes the output unambiguous, even in the presence of file
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| 364 | names containing unusual characters like newlines.
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| 365 | This option can be used with commands like
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| 366 | .BR "find \-print0" ,
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| 367 | .BR "perl \-0" ,
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| 368 | .BR "sort \-z" ,
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| 369 | and
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| 370 | .B "xargs \-0"
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| 371 | to process arbitrary file names,
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| 372 | even those that contain newline characters.
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| 373 | .SS "Context Line Control"
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| 374 | .TP
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| 375 | .BI \-A " NUM" "\fR,\fP \-\^\-after\-context=" NUM
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| 376 | Print
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| 377 | .I NUM
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| 378 | lines of trailing context after matching lines.
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| 379 | Places a line containing a group separator
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| 380 | .RB ( \-\^\- )
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| 381 | between contiguous groups of matches.
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| 382 | With the
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| 383 | .B \-o
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| 384 | or
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| 385 | .B \-\^\-only\-matching
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| 386 | option, this has no effect and a warning is given.
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| 387 | .TP
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| 388 | .BI \-B " NUM" "\fR,\fP \-\^\-before\-context=" NUM
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| 389 | Print
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| 390 | .I NUM
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|---|
| 391 | lines of leading context before matching lines.
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| 392 | Places a line containing a group separator
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|---|
| 393 | .RB ( \-\^\- )
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| 394 | between contiguous groups of matches.
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| 395 | With the
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| 396 | .B \-o
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|---|
| 397 | or
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| 398 | .B \-\^\-only\-matching
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|---|
| 399 | option, this has no effect and a warning is given.
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| 400 | .TP
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| 401 | .BI \-C " NUM" "\fR,\fP \-" NUM "\fR,\fP \-\^\-context=" NUM
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|---|
| 402 | Print
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| 403 | .I NUM
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|---|
| 404 | lines of output context.
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|---|
| 405 | Places a line containing a group separator
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|---|
| 406 | .RB ( \-\^\- )
|
|---|
| 407 | between contiguous groups of matches.
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|---|
| 408 | With the
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| 409 | .B \-o
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|---|
| 410 | or
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| 411 | .B \-\^\-only\-matching
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|---|
| 412 | option, this has no effect and a warning is given.
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|---|
| 413 | .SS "File and Directory Selection"
|
|---|
| 414 | .TP
|
|---|
| 415 | .BR \-a ", " \-\^\-text
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|---|
| 416 | Process a binary file as if it were text; this is equivalent to the
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| 417 | .B \-\^\-binary\-files=text
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| 418 | option.
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| 419 | .TP
|
|---|
| 420 | .BI \-\^\-binary\-files= TYPE
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|---|
| 421 | If the first few bytes of a file indicate that the file contains binary
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| 422 | data, assume that the file is of type
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| 423 | .IR TYPE .
|
|---|
| 424 | By default,
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| 425 | .I TYPE
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|---|
| 426 | is
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| 427 | .BR binary ,
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| 428 | and
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|---|
| 429 | .B grep
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|---|
| 430 | normally outputs either
|
|---|
| 431 | a one-line message saying that a binary file matches, or no message if
|
|---|
| 432 | there is no match.
|
|---|
| 433 | If
|
|---|
| 434 | .I TYPE
|
|---|
| 435 | is
|
|---|
| 436 | .BR without-match ,
|
|---|
| 437 | .B grep
|
|---|
| 438 | assumes that a binary file does not match; this is equivalent to the
|
|---|
| 439 | .B \-I
|
|---|
| 440 | option.
|
|---|
| 441 | If
|
|---|
| 442 | .I TYPE
|
|---|
| 443 | is
|
|---|
| 444 | .BR text ,
|
|---|
| 445 | .B grep
|
|---|
| 446 | processes a binary file as if it were text; this is equivalent to the
|
|---|
| 447 | .B \-a
|
|---|
| 448 | option.
|
|---|
| 449 | .I Warning:
|
|---|
| 450 | .B "grep \-\^\-binary\-files=text"
|
|---|
| 451 | might output binary garbage,
|
|---|
| 452 | which can have nasty side effects if the output is a terminal and if the
|
|---|
| 453 | terminal driver interprets some of it as commands.
|
|---|
| 454 | .TP
|
|---|
| 455 | .BI \-D " ACTION" "\fR,\fP \-\^\-devices=" ACTION
|
|---|
| 456 | If an input file is a device, FIFO or socket, use
|
|---|
| 457 | .I ACTION
|
|---|
| 458 | to process it.
|
|---|
| 459 | By default,
|
|---|
| 460 | .I ACTION
|
|---|
| 461 | is
|
|---|
| 462 | .BR read ,
|
|---|
| 463 | which means that devices are read just as if they were ordinary files.
|
|---|
| 464 | If
|
|---|
| 465 | .I ACTION
|
|---|
| 466 | is
|
|---|
| 467 | .BR skip ,
|
|---|
| 468 | devices are silently skipped.
|
|---|
| 469 | .TP
|
|---|
| 470 | .BI \-d " ACTION" "\fR,\fP \-\^\-directories=" ACTION
|
|---|
| 471 | If an input file is a directory, use
|
|---|
| 472 | .I ACTION
|
|---|
| 473 | to process it.
|
|---|
| 474 | By default,
|
|---|
| 475 | .I ACTION
|
|---|
| 476 | is
|
|---|
| 477 | .BR read ,
|
|---|
| 478 | which means that directories are read just as if they were ordinary files.
|
|---|
| 479 | If
|
|---|
| 480 | .I ACTION
|
|---|
| 481 | is
|
|---|
| 482 | .BR skip ,
|
|---|
| 483 | directories are silently skipped.
|
|---|
| 484 | If
|
|---|
| 485 | .I ACTION
|
|---|
| 486 | is
|
|---|
| 487 | .BR recurse ,
|
|---|
| 488 | .B grep
|
|---|
| 489 | reads all files under each directory, recursively;
|
|---|
| 490 | this is equivalent to the
|
|---|
| 491 | .B \-r
|
|---|
| 492 | option.
|
|---|
| 493 | .TP
|
|---|
| 494 | .BI \-\^\-exclude= GLOB
|
|---|
| 495 | Skip files whose base name matches
|
|---|
| 496 | .I GLOB
|
|---|
| 497 | (using wildcard matching).
|
|---|
| 498 | A file-name glob can use
|
|---|
| 499 | .BR * ,
|
|---|
| 500 | .BR ? ,
|
|---|
| 501 | and
|
|---|
| 502 | .BR [ ... ]
|
|---|
| 503 | as wildcards, and
|
|---|
| 504 | .B \e
|
|---|
| 505 | to quote a wildcard or backslash character literally.
|
|---|
| 506 | .TP
|
|---|
| 507 | .BI \-\^\-exclude-from= FILE
|
|---|
| 508 | Skip files whose base name matches any of the file-name globs read from
|
|---|
| 509 | .I FILE
|
|---|
| 510 | (using wildcard matching as described under
|
|---|
| 511 | .BR \-\^\-exclude ).
|
|---|
| 512 | .TP
|
|---|
| 513 | .BI \-\^\-exclude-dir= DIR
|
|---|
| 514 | Exclude directories matching the pattern
|
|---|
| 515 | .I DIR
|
|---|
| 516 | from recursive searches.
|
|---|
| 517 | .TP
|
|---|
| 518 | .BR \-I
|
|---|
| 519 | Process a binary file as if it did not contain matching data; this is
|
|---|
| 520 | equivalent to the
|
|---|
| 521 | .B \-\^\-binary\-files=without-match
|
|---|
| 522 | option.
|
|---|
| 523 | .TP
|
|---|
| 524 | .BI \-\^\-include= GLOB
|
|---|
| 525 | Search only files whose base name matches
|
|---|
| 526 | .I GLOB
|
|---|
| 527 | (using wildcard matching as described under
|
|---|
| 528 | .BR \-\^\-exclude ).
|
|---|
| 529 | .TP
|
|---|
| 530 | .BR \-R ", " \-r ", " \-\^\-recursive
|
|---|
| 531 | Read all files under each directory, recursively;
|
|---|
| 532 | this is equivalent to the
|
|---|
| 533 | .B "\-d recurse"
|
|---|
| 534 | option.
|
|---|
| 535 | .SS "Other Options"
|
|---|
| 536 | .TP
|
|---|
| 537 | .BR \-\^\-line\-buffered
|
|---|
| 538 | Use line buffering on output.
|
|---|
| 539 | This can cause a performance penalty.
|
|---|
| 540 | .TP
|
|---|
| 541 | .B \-\^\-mmap
|
|---|
| 542 | If possible, use the
|
|---|
| 543 | .BR mmap (2)
|
|---|
| 544 | system call to read input, instead of
|
|---|
| 545 | the default
|
|---|
| 546 | .BR read (2)
|
|---|
| 547 | system call.
|
|---|
| 548 | In some situations,
|
|---|
| 549 | .B \-\^\-mmap
|
|---|
| 550 | yields better performance.
|
|---|
| 551 | However,
|
|---|
| 552 | .B \-\^\-mmap
|
|---|
| 553 | can cause undefined behavior (including core dumps)
|
|---|
| 554 | if an input file shrinks while
|
|---|
| 555 | .B grep
|
|---|
| 556 | is operating, or if an I/O error occurs.
|
|---|
| 557 | .TP
|
|---|
| 558 | .BR \-U ", " \-\^\-binary
|
|---|
| 559 | Treat the file(s) as binary.
|
|---|
| 560 | By default, under \s-1MS-DOS\s0 and \s-1MS\s0-Windows,
|
|---|
| 561 | .BR grep
|
|---|
| 562 | guesses the file type by looking at the contents of the first 32KB
|
|---|
| 563 | read from the file.
|
|---|
| 564 | If
|
|---|
| 565 | .BR grep
|
|---|
| 566 | decides the file is a text file, it strips the CR characters from the
|
|---|
| 567 | original file contents (to make regular expressions with
|
|---|
| 568 | .B ^
|
|---|
| 569 | and
|
|---|
| 570 | .B $
|
|---|
| 571 | work correctly).
|
|---|
| 572 | Specifying
|
|---|
| 573 | .B \-U
|
|---|
| 574 | overrules this guesswork, causing all files to be read and passed to the
|
|---|
| 575 | matching mechanism verbatim; if the file is a text file with CR/LF
|
|---|
| 576 | pairs at the end of each line, this will cause some regular
|
|---|
| 577 | expressions to fail.
|
|---|
| 578 | This option has no effect on platforms
|
|---|
| 579 | other than \s-1MS-DOS\s0 and \s-1MS\s0-Windows.
|
|---|
| 580 | .TP
|
|---|
| 581 | .BR \-z ", " \-\^\-null\-data
|
|---|
| 582 | Treat the input as a set of lines,
|
|---|
| 583 | each terminated by a zero byte (the \s-1ASCII\s0
|
|---|
| 584 | .B NUL
|
|---|
| 585 | character) instead of a newline.
|
|---|
| 586 | Like the
|
|---|
| 587 | .B -Z
|
|---|
| 588 | or
|
|---|
| 589 | .B \-\^\-null
|
|---|
| 590 | option, this option can be used with commands like
|
|---|
| 591 | .B sort -z
|
|---|
| 592 | to process arbitrary file names.
|
|---|
| 593 | .
|
|---|
| 594 | .SH "REGULAR EXPRESSIONS"
|
|---|
| 595 | A regular expression is a pattern that describes a set of strings.
|
|---|
| 596 | Regular expressions are constructed analogously to arithmetic
|
|---|
| 597 | expressions, by using various operators to combine smaller expressions.
|
|---|
| 598 | .PP
|
|---|
| 599 | .B grep
|
|---|
| 600 | understands three different versions of regular expression syntax:
|
|---|
| 601 | \*(lqbasic,\*(rq \*(lqextended\*(rq and \*(lqperl.\*(rq In
|
|---|
| 602 | .RB "\s-1GNU\s0\ " grep ,
|
|---|
| 603 | there is no difference in available functionality between basic and
|
|---|
| 604 | extended syntaxes.
|
|---|
| 605 | In other implementations, basic regular expressions are less powerful.
|
|---|
| 606 | The following description applies to extended regular expressions;
|
|---|
| 607 | differences for basic regular expressions are summarized afterwards.
|
|---|
| 608 | Perl regular expressions give additional functionality, and are
|
|---|
| 609 | documented in pcresyntax(3) and pcrepattern(3), but may not be
|
|---|
| 610 | available on every system.
|
|---|
| 611 | .PP
|
|---|
| 612 | The fundamental building blocks are the regular expressions
|
|---|
| 613 | that match a single character.
|
|---|
| 614 | Most characters, including all letters and digits,
|
|---|
| 615 | are regular expressions that match themselves.
|
|---|
| 616 | Any meta-character with special meaning
|
|---|
| 617 | may be quoted by preceding it with a backslash.
|
|---|
| 618 | .PP
|
|---|
| 619 | The period
|
|---|
| 620 | .B .\&
|
|---|
| 621 | matches any single character.
|
|---|
| 622 | .SS "Character Classes and Bracket Expressions"
|
|---|
| 623 | A
|
|---|
| 624 | .I "bracket expression"
|
|---|
| 625 | is a list of characters enclosed by
|
|---|
| 626 | .B [
|
|---|
| 627 | and
|
|---|
| 628 | .BR ] .
|
|---|
| 629 | It matches any single
|
|---|
| 630 | character in that list; if the first character of the list
|
|---|
| 631 | is the caret
|
|---|
| 632 | .B ^
|
|---|
| 633 | then it matches any character
|
|---|
| 634 | .I not
|
|---|
| 635 | in the list.
|
|---|
| 636 | For example, the regular expression
|
|---|
| 637 | .B [0123456789]
|
|---|
| 638 | matches any single digit.
|
|---|
| 639 | .PP
|
|---|
| 640 | Within a bracket expression, a
|
|---|
| 641 | .I "range expression"
|
|---|
| 642 | consists of two characters separated by a hyphen.
|
|---|
| 643 | It matches any single character that sorts between the two characters,
|
|---|
| 644 | inclusive, using the locale's collating sequence and character set.
|
|---|
| 645 | For example, in the default C locale,
|
|---|
| 646 | .B [a\-d]
|
|---|
| 647 | is equivalent to
|
|---|
| 648 | .BR [abcd] .
|
|---|
| 649 | Many locales sort characters in dictionary order, and in these locales
|
|---|
| 650 | .B [a\-d]
|
|---|
| 651 | is typically not equivalent to
|
|---|
| 652 | .BR [abcd] ;
|
|---|
| 653 | it might be equivalent to
|
|---|
| 654 | .BR [aBbCcDd] ,
|
|---|
| 655 | for example.
|
|---|
| 656 | To obtain the traditional interpretation of bracket expressions,
|
|---|
| 657 | you can use the C locale by setting the
|
|---|
| 658 | .B LC_ALL
|
|---|
| 659 | environment variable to the value
|
|---|
| 660 | .BR C .
|
|---|
| 661 | .PP
|
|---|
| 662 | Finally, certain named classes of characters are predefined within
|
|---|
| 663 | bracket expressions, as follows.
|
|---|
| 664 | Their names are self explanatory, and they are
|
|---|
| 665 | .BR [:alnum:] ,
|
|---|
| 666 | .BR [:alpha:] ,
|
|---|
| 667 | .BR [:cntrl:] ,
|
|---|
| 668 | .BR [:digit:] ,
|
|---|
| 669 | .BR [:graph:] ,
|
|---|
| 670 | .BR [:lower:] ,
|
|---|
| 671 | .BR [:print:] ,
|
|---|
| 672 | .BR [:punct:] ,
|
|---|
| 673 | .BR [:space:] ,
|
|---|
| 674 | .BR [:upper:] ,
|
|---|
| 675 | and
|
|---|
| 676 | .BR [:xdigit:].
|
|---|
| 677 | For example,
|
|---|
| 678 | .B [[:alnum:]]
|
|---|
| 679 | means the character class of numbers and
|
|---|
| 680 | letters in the current locale. In the C locale and \s-1ASCII\s0
|
|---|
| 681 | character set encoding, this is the same as
|
|---|
| 682 | .BR [0\-9A\-Za\-z] .
|
|---|
| 683 | (Note that the brackets in these class names are part of the symbolic
|
|---|
| 684 | names, and must be included in addition to the brackets delimiting
|
|---|
| 685 | the bracket expression.)
|
|---|
| 686 | Most meta-characters lose their special meaning inside bracket expressions.
|
|---|
| 687 | To include a literal
|
|---|
| 688 | .B ]
|
|---|
| 689 | place it first in the list.
|
|---|
| 690 | Similarly, to include a literal
|
|---|
| 691 | .B ^
|
|---|
| 692 | place it anywhere but first.
|
|---|
| 693 | Finally, to include a literal
|
|---|
| 694 | .B \-
|
|---|
| 695 | place it last.
|
|---|
| 696 | .SS Anchoring
|
|---|
| 697 | The caret
|
|---|
| 698 | .B ^
|
|---|
| 699 | and the dollar sign
|
|---|
| 700 | .B $
|
|---|
| 701 | are meta-characters that respectively match the empty string at the
|
|---|
| 702 | beginning and end of a line.
|
|---|
| 703 | .SS "The Backslash Character and Special Expressions"
|
|---|
| 704 | The symbols
|
|---|
| 705 | .B \e<
|
|---|
| 706 | and
|
|---|
| 707 | .B \e>
|
|---|
| 708 | respectively match the empty string at the beginning and end of a word.
|
|---|
| 709 | The symbol
|
|---|
| 710 | .B \eb
|
|---|
| 711 | matches the empty string at the edge of a word,
|
|---|
| 712 | and
|
|---|
| 713 | .B \eB
|
|---|
| 714 | matches the empty string provided it's
|
|---|
| 715 | .I not
|
|---|
| 716 | at the edge of a word.
|
|---|
| 717 | The symbol
|
|---|
| 718 | .B \ew
|
|---|
| 719 | is a synonym for
|
|---|
| 720 | .B [_[:alnum:]]
|
|---|
| 721 | and
|
|---|
| 722 | .B \eW
|
|---|
| 723 | is a synonym for
|
|---|
| 724 | .BR [^_[:alnum:]] .
|
|---|
| 725 | .SS Repetition
|
|---|
| 726 | A regular expression may be followed by one of several repetition operators:
|
|---|
| 727 | .PD 0
|
|---|
| 728 | .TP
|
|---|
| 729 | .B ?
|
|---|
| 730 | The preceding item is optional and matched at most once.
|
|---|
| 731 | .TP
|
|---|
| 732 | .B *
|
|---|
| 733 | The preceding item will be matched zero or more times.
|
|---|
| 734 | .TP
|
|---|
| 735 | .B +
|
|---|
| 736 | The preceding item will be matched one or more times.
|
|---|
| 737 | .TP
|
|---|
| 738 | .BI { n }
|
|---|
| 739 | The preceding item is matched exactly
|
|---|
| 740 | .I n
|
|---|
| 741 | times.
|
|---|
| 742 | .TP
|
|---|
| 743 | .BI { n ,}
|
|---|
| 744 | The preceding item is matched
|
|---|
| 745 | .I n
|
|---|
| 746 | or more times.
|
|---|
| 747 | .TP
|
|---|
| 748 | .BI { n , m }
|
|---|
| 749 | The preceding item is matched at least
|
|---|
| 750 | .I n
|
|---|
| 751 | times, but not more than
|
|---|
| 752 | .I m
|
|---|
| 753 | times.
|
|---|
| 754 | .PD
|
|---|
| 755 | .SS Concatenation
|
|---|
| 756 | Two regular expressions may be concatenated; the resulting
|
|---|
| 757 | regular expression matches any string formed by concatenating
|
|---|
| 758 | two substrings that respectively match the concatenated
|
|---|
| 759 | expressions.
|
|---|
| 760 | .SS Alternation
|
|---|
| 761 | Two regular expressions may be joined by the infix operator
|
|---|
| 762 | .BR | ;
|
|---|
| 763 | the resulting regular expression matches any string matching
|
|---|
| 764 | either alternate expression.
|
|---|
| 765 | .SS Precedence
|
|---|
| 766 | Repetition takes precedence over concatenation, which in turn
|
|---|
| 767 | takes precedence over alternation.
|
|---|
| 768 | A whole expression may be enclosed in parentheses
|
|---|
| 769 | to override these precedence rules and form a subexpression.
|
|---|
| 770 | .SS "Back References and Subexpressions"
|
|---|
| 771 | The back-reference
|
|---|
| 772 | .BI \e n\c
|
|---|
| 773 | \&, where
|
|---|
| 774 | .I n
|
|---|
| 775 | is a single digit, matches the substring
|
|---|
| 776 | previously matched by the
|
|---|
| 777 | .IR n th
|
|---|
| 778 | parenthesized subexpression of the regular expression.
|
|---|
| 779 | .SS "Basic vs Extended Regular Expressions"
|
|---|
| 780 | In basic regular expressions the meta-characters
|
|---|
| 781 | .BR ? ,
|
|---|
| 782 | .BR + ,
|
|---|
| 783 | .BR { ,
|
|---|
| 784 | .BR | ,
|
|---|
| 785 | .BR ( ,
|
|---|
| 786 | and
|
|---|
| 787 | .BR )
|
|---|
| 788 | lose their special meaning; instead use the backslashed
|
|---|
| 789 | versions
|
|---|
| 790 | .BR \e? ,
|
|---|
| 791 | .BR \e+ ,
|
|---|
| 792 | .BR \e{ ,
|
|---|
| 793 | .BR \e| ,
|
|---|
| 794 | .BR \e( ,
|
|---|
| 795 | and
|
|---|
| 796 | .BR \e) .
|
|---|
| 797 | .PP
|
|---|
| 798 | Traditional
|
|---|
| 799 | .B egrep
|
|---|
| 800 | did not support the
|
|---|
| 801 | .B {
|
|---|
| 802 | meta-character, and some
|
|---|
| 803 | .B egrep
|
|---|
| 804 | implementations support
|
|---|
| 805 | .B \e{
|
|---|
| 806 | instead, so portable scripts should avoid
|
|---|
| 807 | .B {
|
|---|
| 808 | in
|
|---|
| 809 | .B "grep\ \-E"
|
|---|
| 810 | patterns and should use
|
|---|
| 811 | .B [{]
|
|---|
| 812 | to match a literal
|
|---|
| 813 | .BR { .
|
|---|
| 814 | .PP
|
|---|
| 815 | \s-1GNU\s0
|
|---|
| 816 | .B "grep\ \-E"
|
|---|
| 817 | attempts to support traditional usage by assuming that
|
|---|
| 818 | .B {
|
|---|
| 819 | is not special if it would be the start of an invalid interval
|
|---|
| 820 | specification.
|
|---|
| 821 | For example, the command
|
|---|
| 822 | .B "grep\ \-E\ '{1'"
|
|---|
| 823 | searches for the two-character string
|
|---|
| 824 | .B {1
|
|---|
| 825 | instead of reporting a syntax error in the regular expression.
|
|---|
| 826 | \s-1POSIX.2\s0 allows this behavior as an extension, but portable scripts
|
|---|
| 827 | should avoid it.
|
|---|
| 828 | .
|
|---|
| 829 | .SH "ENVIRONMENT VARIABLES"
|
|---|
| 830 | The behavior of
|
|---|
| 831 | .B grep
|
|---|
| 832 | is affected by the following environment variables.
|
|---|
| 833 | .PP
|
|---|
| 834 | The locale for category
|
|---|
| 835 | .BI LC_ foo
|
|---|
| 836 | is specified by examining the three environment variables
|
|---|
| 837 | .BR LC_ALL ,
|
|---|
| 838 | .BR LC_\fIfoo\fP ,
|
|---|
| 839 | .BR LANG ,
|
|---|
| 840 | in that order.
|
|---|
| 841 | The first of these variables that is set specifies the locale.
|
|---|
| 842 | For example, if
|
|---|
| 843 | .B LC_ALL
|
|---|
| 844 | is not set, but
|
|---|
| 845 | .B LC_MESSAGES
|
|---|
| 846 | is set to
|
|---|
| 847 | .BR pt_BR ,
|
|---|
| 848 | then the Brazilian Portuguese locale is used for the
|
|---|
| 849 | .B LC_MESSAGES
|
|---|
| 850 | category.
|
|---|
| 851 | The C locale is used if none of these environment variables are set,
|
|---|
| 852 | if the locale catalog is not installed, or if
|
|---|
| 853 | .B grep
|
|---|
| 854 | was not compiled with national language support (\s-1NLS\s0).
|
|---|
| 855 | .TP
|
|---|
| 856 | .B GREP_OPTIONS
|
|---|
| 857 | This variable specifies default options
|
|---|
| 858 | to be placed in front of any explicit options.
|
|---|
| 859 | For example, if
|
|---|
| 860 | .B GREP_OPTIONS
|
|---|
| 861 | is
|
|---|
| 862 | .BR "'\-\^\-binary-files=without-match \-\^\-directories=skip'" ,
|
|---|
| 863 | .B grep
|
|---|
| 864 | behaves as if the two options
|
|---|
| 865 | .B \-\^\-binary\-files=without-match
|
|---|
| 866 | and
|
|---|
| 867 | .B \-\^\-directories=skip
|
|---|
| 868 | had been specified before any explicit options.
|
|---|
| 869 | Option specifications are separated by whitespace.
|
|---|
| 870 | A backslash escapes the next character,
|
|---|
| 871 | so it can be used to specify an option containing whitespace or a backslash.
|
|---|
| 872 | .TP
|
|---|
| 873 | .B GREP_COLOR
|
|---|
| 874 | This variable specifies the color used to highlight matched (non-empty) text.
|
|---|
| 875 | It is deprecated in favor of
|
|---|
| 876 | .BR GREP_COLORS ,
|
|---|
| 877 | but still supported.
|
|---|
| 878 | The
|
|---|
| 879 | .BR mt ,
|
|---|
| 880 | .BR ms ,
|
|---|
| 881 | and
|
|---|
| 882 | .B mc
|
|---|
| 883 | capabilities of
|
|---|
| 884 | .B GREP_COLORS
|
|---|
| 885 | have priority over it.
|
|---|
| 886 | It can only specify the color used to highlight
|
|---|
| 887 | the matching non-empty text in any matching line
|
|---|
| 888 | (a selected line when the
|
|---|
| 889 | .B -v
|
|---|
| 890 | command-line option is omitted,
|
|---|
| 891 | or a context line when
|
|---|
| 892 | .B -v
|
|---|
| 893 | is specified).
|
|---|
| 894 | The default is
|
|---|
| 895 | .BR 01;31 ,
|
|---|
| 896 | which means a bold red foreground text on the terminal's default background.
|
|---|
| 897 | .TP
|
|---|
| 898 | .B GREP_COLORS
|
|---|
| 899 | Specifies the colors and other attributes
|
|---|
| 900 | used to highlight various parts of the output.
|
|---|
| 901 | Its value is a colon-separated list of capabilities
|
|---|
| 902 | that defaults to
|
|---|
| 903 | .B ms=01;31:mc=01;31:sl=:cx=:fn=35:ln=32:bn=32:se=36
|
|---|
| 904 | with the
|
|---|
| 905 | .B rv
|
|---|
| 906 | and
|
|---|
| 907 | .B ne
|
|---|
| 908 | boolean capabilities omitted (i.e., false).
|
|---|
| 909 | Supported capabilities are as follows.
|
|---|
| 910 | .RS
|
|---|
| 911 | .TP
|
|---|
| 912 | .B sl=
|
|---|
| 913 | SGR substring for whole selected lines
|
|---|
| 914 | (i.e.,
|
|---|
| 915 | matching lines when the
|
|---|
| 916 | .B \-v
|
|---|
| 917 | command-line option is omitted,
|
|---|
| 918 | or non-matching lines when
|
|---|
| 919 | .B \-v
|
|---|
| 920 | is specified).
|
|---|
| 921 | If however the boolean
|
|---|
| 922 | .B rv
|
|---|
| 923 | capability
|
|---|
| 924 | and the
|
|---|
| 925 | .B \-v
|
|---|
| 926 | command-line option are both specified,
|
|---|
| 927 | it applies to context matching lines instead.
|
|---|
| 928 | The default is empty (i.e., the terminal's default color pair).
|
|---|
| 929 | .TP
|
|---|
| 930 | .B cx=
|
|---|
| 931 | SGR substring for whole context lines
|
|---|
| 932 | (i.e.,
|
|---|
| 933 | non-matching lines when the
|
|---|
| 934 | .B \-v
|
|---|
| 935 | command-line option is omitted,
|
|---|
| 936 | or matching lines when
|
|---|
| 937 | .B \-v
|
|---|
| 938 | is specified).
|
|---|
| 939 | If however the boolean
|
|---|
| 940 | .B rv
|
|---|
| 941 | capability
|
|---|
| 942 | and the
|
|---|
| 943 | .B \-v
|
|---|
| 944 | command-line option are both specified,
|
|---|
| 945 | it applies to selected non-matching lines instead.
|
|---|
| 946 | The default is empty (i.e., the terminal's default color pair).
|
|---|
| 947 | .TP
|
|---|
| 948 | .B rv
|
|---|
| 949 | Boolean value that reverses (swaps) the meanings of
|
|---|
| 950 | the
|
|---|
| 951 | .B sl=
|
|---|
| 952 | and
|
|---|
| 953 | .B cx=
|
|---|
| 954 | capabilities
|
|---|
| 955 | when the
|
|---|
| 956 | .B \-v
|
|---|
| 957 | command-line option is specified.
|
|---|
| 958 | The default is false (i.e., the capability is omitted).
|
|---|
| 959 | .TP
|
|---|
| 960 | .B mt=01;31
|
|---|
| 961 | SGR substring for matching non-empty text in any matching line
|
|---|
| 962 | (i.e.,
|
|---|
| 963 | a selected line when the
|
|---|
| 964 | .B \-v
|
|---|
| 965 | command-line option is omitted,
|
|---|
| 966 | or a context line when
|
|---|
| 967 | .B \-v
|
|---|
| 968 | is specified).
|
|---|
| 969 | Setting this is equivalent to setting both
|
|---|
| 970 | .B ms=
|
|---|
| 971 | and
|
|---|
| 972 | .B mc=
|
|---|
| 973 | at once to the same value.
|
|---|
| 974 | The default is a bold red text foreground over the current line background.
|
|---|
| 975 | .TP
|
|---|
| 976 | .B ms=01;31
|
|---|
| 977 | SGR substring for matching non-empty text in a selected line.
|
|---|
| 978 | (This is only used when the
|
|---|
| 979 | .B \-v
|
|---|
| 980 | command-line option is omitted.)
|
|---|
| 981 | The effect of the
|
|---|
| 982 | .B sl=
|
|---|
| 983 | (or
|
|---|
| 984 | .B cx=
|
|---|
| 985 | if
|
|---|
| 986 | .BR rv )
|
|---|
| 987 | capability remains active when this kicks in.
|
|---|
| 988 | The default is a bold red text foreground over the current line background.
|
|---|
| 989 | .TP
|
|---|
| 990 | .B mc=01;31
|
|---|
| 991 | SGR substring for matching non-empty text in a context line.
|
|---|
| 992 | (This is only used when the
|
|---|
| 993 | .B \-v
|
|---|
| 994 | command-line option is specified.)
|
|---|
| 995 | The effect of the
|
|---|
| 996 | .B cx=
|
|---|
| 997 | (or
|
|---|
| 998 | .B sl=
|
|---|
| 999 | if
|
|---|
| 1000 | .BR rv )
|
|---|
| 1001 | capability remains active when this kicks in.
|
|---|
| 1002 | The default is a bold red text foreground over the current line background.
|
|---|
| 1003 | .TP
|
|---|
| 1004 | .B fn=35
|
|---|
| 1005 | SGR substring for file names prefixing any content line.
|
|---|
| 1006 | The default is a magenta text foreground over the terminal's default background.
|
|---|
| 1007 | .TP
|
|---|
| 1008 | .B ln=32
|
|---|
| 1009 | SGR substring for line numbers prefixing any content line.
|
|---|
| 1010 | The default is a green text foreground over the terminal's default background.
|
|---|
| 1011 | .TP
|
|---|
| 1012 | .B bn=32
|
|---|
| 1013 | SGR substring for byte offsets prefixing any content line.
|
|---|
| 1014 | The default is a green text foreground over the terminal's default background.
|
|---|
| 1015 | .TP
|
|---|
| 1016 | .B se=36
|
|---|
| 1017 | SGR substring for separators that are inserted
|
|---|
| 1018 | between selected line fields
|
|---|
| 1019 | .RB ( : ),
|
|---|
| 1020 | between context line fields,
|
|---|
| 1021 | .RB ( \- ),
|
|---|
| 1022 | and between groups of adjacent lines when nonzero context is specified
|
|---|
| 1023 | .RB ( \-\^\- ).
|
|---|
| 1024 | The default is a cyan text foreground over the terminal's default background.
|
|---|
| 1025 | .TP
|
|---|
| 1026 | .B ne
|
|---|
| 1027 | Boolean value that prevents clearing to the end of line
|
|---|
| 1028 | using Erase in Line (EL) to Right
|
|---|
| 1029 | .RB ( \\\\\\33[K )
|
|---|
| 1030 | each time a colorized item ends.
|
|---|
| 1031 | This is needed on terminals on which EL is not supported.
|
|---|
| 1032 | It is otherwise useful on terminals
|
|---|
| 1033 | for which the
|
|---|
| 1034 | .B back_color_erase
|
|---|
| 1035 | .RB ( bce )
|
|---|
| 1036 | boolean terminfo capability does not apply,
|
|---|
| 1037 | when the chosen highlight colors do not affect the background,
|
|---|
| 1038 | or when EL is too slow or causes too much flicker.
|
|---|
| 1039 | The default is false (i.e., the capability is omitted).
|
|---|
| 1040 | .PP
|
|---|
| 1041 | Note that boolean capabilities have no
|
|---|
| 1042 | .BR = ...
|
|---|
| 1043 | part.
|
|---|
| 1044 | They are omitted (i.e., false) by default and become true when specified.
|
|---|
| 1045 | .PP
|
|---|
| 1046 | See the Select Graphic Rendition (SGR) section
|
|---|
| 1047 | in the documentation of the text terminal that is used
|
|---|
| 1048 | for permitted values and their meaning as character attributes.
|
|---|
| 1049 | These substring values are integers in decimal representation
|
|---|
| 1050 | and can be concatenated with semicolons.
|
|---|
| 1051 | .B grep
|
|---|
| 1052 | takes care of assembling the result
|
|---|
| 1053 | into a complete SGR sequence
|
|---|
| 1054 | .RB ( \\\\\\33[ ... m ).
|
|---|
| 1055 | Common values to concatenate include
|
|---|
| 1056 | .B 1
|
|---|
| 1057 | for bold,
|
|---|
| 1058 | .B 4
|
|---|
| 1059 | for underline,
|
|---|
| 1060 | .B 5
|
|---|
| 1061 | for blink,
|
|---|
| 1062 | .B 7
|
|---|
| 1063 | for inverse,
|
|---|
| 1064 | .B 39
|
|---|
| 1065 | for default foreground color,
|
|---|
| 1066 | .B 30
|
|---|
| 1067 | to
|
|---|
| 1068 | .B 37
|
|---|
| 1069 | for foreground colors,
|
|---|
| 1070 | .B 90
|
|---|
| 1071 | to
|
|---|
| 1072 | .B 97
|
|---|
| 1073 | for 16-color mode foreground colors,
|
|---|
| 1074 | .B 38;5;0
|
|---|
| 1075 | to
|
|---|
| 1076 | .B 38;5;255
|
|---|
| 1077 | for 88-color and 256-color modes foreground colors,
|
|---|
| 1078 | .B 49
|
|---|
| 1079 | for default background color,
|
|---|
| 1080 | .B 40
|
|---|
| 1081 | to
|
|---|
| 1082 | .B 47
|
|---|
| 1083 | for background colors,
|
|---|
| 1084 | .B 100
|
|---|
| 1085 | to
|
|---|
| 1086 | .B 107
|
|---|
| 1087 | for 16-color mode background colors, and
|
|---|
| 1088 | .B 48;5;0
|
|---|
| 1089 | to
|
|---|
| 1090 | .B 48;5;255
|
|---|
| 1091 | for 88-color and 256-color modes background colors.
|
|---|
| 1092 | .RE
|
|---|
| 1093 | .TP
|
|---|
| 1094 | \fBLC_ALL\fP, \fBLC_COLLATE\fP, \fBLANG\fP
|
|---|
| 1095 | These variables specify the locale for the
|
|---|
| 1096 | .B LC_COLLATE
|
|---|
| 1097 | category,
|
|---|
| 1098 | which determines the collating sequence
|
|---|
| 1099 | used to interpret range expressions like
|
|---|
| 1100 | .BR [a\-z] .
|
|---|
| 1101 | .TP
|
|---|
| 1102 | \fBLC_ALL\fP, \fBLC_CTYPE\fP, \fBLANG\fP
|
|---|
| 1103 | These variables specify the locale for the
|
|---|
| 1104 | .B LC_CTYPE
|
|---|
| 1105 | category,
|
|---|
| 1106 | which determines the type of characters,
|
|---|
| 1107 | e.g., which characters are whitespace.
|
|---|
| 1108 | .TP
|
|---|
| 1109 | \fBLC_ALL\fP, \fBLC_MESSAGES\fP, \fBLANG\fP
|
|---|
| 1110 | These variables specify the locale for the
|
|---|
| 1111 | .B LC_MESSAGES
|
|---|
| 1112 | category,
|
|---|
| 1113 | which determines the language that
|
|---|
| 1114 | .B grep
|
|---|
| 1115 | uses for messages.
|
|---|
| 1116 | The default C locale uses American English messages.
|
|---|
| 1117 | .TP
|
|---|
| 1118 | .B POSIXLY_CORRECT
|
|---|
| 1119 | If set,
|
|---|
| 1120 | .B grep
|
|---|
| 1121 | behaves as \s-1POSIX.2\s0 requires; otherwise,
|
|---|
| 1122 | .B grep
|
|---|
| 1123 | behaves more like other \s-1GNU\s0 programs.
|
|---|
| 1124 | \s-1POSIX.2\s0 requires that options that follow file names must be
|
|---|
| 1125 | treated as file names; by default, such options are permuted to the
|
|---|
| 1126 | front of the operand list and are treated as options.
|
|---|
| 1127 | Also, \s-1POSIX.2\s0 requires that unrecognized options be diagnosed as
|
|---|
| 1128 | \*(lqillegal\*(rq, but since they are not really against the law the default
|
|---|
| 1129 | is to diagnose them as \*(lqinvalid\*(rq.
|
|---|
| 1130 | .B POSIXLY_CORRECT
|
|---|
| 1131 | also disables \fB_\fP\fIN\fP\fB_GNU_nonoption_argv_flags_\fP,
|
|---|
| 1132 | described below.
|
|---|
| 1133 | .TP
|
|---|
| 1134 | \fB_\fP\fIN\fP\fB_GNU_nonoption_argv_flags_\fP
|
|---|
| 1135 | (Here
|
|---|
| 1136 | .I N
|
|---|
| 1137 | is
|
|---|
| 1138 | .BR grep 's
|
|---|
| 1139 | numeric process ID.) If the
|
|---|
| 1140 | .IR i th
|
|---|
| 1141 | character of this environment variable's value is
|
|---|
| 1142 | .BR 1 ,
|
|---|
| 1143 | do not consider the
|
|---|
| 1144 | .IR i th
|
|---|
| 1145 | operand of
|
|---|
| 1146 | .B grep
|
|---|
| 1147 | to be an option, even if it appears to be one.
|
|---|
| 1148 | A shell can put this variable in the environment for each command it runs,
|
|---|
| 1149 | specifying which operands are the results of file name wildcard
|
|---|
| 1150 | expansion and therefore should not be treated as options.
|
|---|
| 1151 | This behavior is available only with the \s-1GNU\s0 C library, and only
|
|---|
| 1152 | when
|
|---|
| 1153 | .B POSIXLY_CORRECT
|
|---|
| 1154 | is not set.
|
|---|
| 1155 | .
|
|---|
| 1156 | .SH "EXIT STATUS"
|
|---|
| 1157 | Normally, the exit status is 0 if selected lines are found and 1 otherwise.
|
|---|
| 1158 | But the exit status is 2 if an error occurred, unless the
|
|---|
| 1159 | .B \-q
|
|---|
| 1160 | or
|
|---|
| 1161 | .B \-\^\-quiet
|
|---|
| 1162 | or
|
|---|
| 1163 | .B \-\^\-silent
|
|---|
| 1164 | option is used and a selected line is found.
|
|---|
| 1165 | Note, however, that \s-1POSIX\s0 only mandates, for programs such as
|
|---|
| 1166 | .BR grep ,
|
|---|
| 1167 | .BR cmp ,
|
|---|
| 1168 | and
|
|---|
| 1169 | .BR diff ,
|
|---|
| 1170 | that the exit status in case of error be greater than 1;
|
|---|
| 1171 | it is therefore advisable, for the sake of portability,
|
|---|
| 1172 | to use logic that tests for this general condition
|
|---|
| 1173 | instead of strict equality with\ 2.
|
|---|
| 1174 | .
|
|---|
| 1175 | .SH COPYRIGHT
|
|---|
| 1176 | Copyright 1998-2000, 2002, 2005-2012 Free Software Foundation, Inc.
|
|---|
| 1177 | .PP
|
|---|
| 1178 | This is free software;
|
|---|
| 1179 | see the source for copying conditions.
|
|---|
| 1180 | There is NO warranty;
|
|---|
| 1181 | not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|---|
| 1182 | .
|
|---|
| 1183 | .SH BUGS
|
|---|
| 1184 | .SS "Reporting Bugs"
|
|---|
| 1185 | Email bug reports to
|
|---|
| 1186 | .RB < bug\-grep@gnu.org >,
|
|---|
| 1187 | a mailing list whose web page is
|
|---|
| 1188 | .RB < http://lists.gnu.org/mailman/listinfo/bug\-grep >.
|
|---|
| 1189 | .BR grep 's
|
|---|
| 1190 | Savannah bug tracker is located at
|
|---|
| 1191 | .RB < http://savannah.gnu.org/bugs/?group=grep >.
|
|---|
| 1192 | .SS "Known Bugs"
|
|---|
| 1193 | Large repetition counts in the
|
|---|
| 1194 | .BI { n , m }
|
|---|
| 1195 | construct may cause
|
|---|
| 1196 | .B grep
|
|---|
| 1197 | to use lots of memory.
|
|---|
| 1198 | In addition,
|
|---|
| 1199 | certain other obscure regular expressions require exponential time
|
|---|
| 1200 | and space, and may cause
|
|---|
| 1201 | .B grep
|
|---|
| 1202 | to run out of memory.
|
|---|
| 1203 | .PP
|
|---|
| 1204 | Back-references are very slow, and may require exponential time.
|
|---|
| 1205 | .
|
|---|
| 1206 | .SH "SEE ALSO"
|
|---|
| 1207 | .SS "Regular Manual Pages"
|
|---|
| 1208 | awk(1), cmp(1), diff(1), find(1), gzip(1),
|
|---|
| 1209 | perl(1), sed(1), sort(1), xargs(1), zgrep(1),
|
|---|
| 1210 | mmap(2), read(2),
|
|---|
| 1211 | pcre(3), pcresyntax(3), pcrepattern(3),
|
|---|
| 1212 | terminfo(5),
|
|---|
| 1213 | glob(7), regex(7).
|
|---|
| 1214 | .SS "\s-1POSIX\s0 Programmer's Manual Page"
|
|---|
| 1215 | grep(1p).
|
|---|
| 1216 | .SS "\*(Txinfo Documentation"
|
|---|
| 1217 | The full documentation for
|
|---|
| 1218 | .B grep
|
|---|
| 1219 | is maintained as a \*(Txinfo manual.
|
|---|
| 1220 | If the
|
|---|
| 1221 | .B info
|
|---|
| 1222 | and
|
|---|
| 1223 | .B grep
|
|---|
| 1224 | programs are properly installed at your site, the command
|
|---|
| 1225 | .IP
|
|---|
| 1226 | .B info grep
|
|---|
| 1227 | .PP
|
|---|
| 1228 | should give you access to the complete manual.
|
|---|
| 1229 | .
|
|---|
| 1230 | .SH NOTES
|
|---|
| 1231 | \s-1GNU\s0's not Unix, but Unix is a beast;
|
|---|
| 1232 | its plural form is Unixen.
|
|---|
| 1233 | .\" Work around problems with some troff -man implementations.
|
|---|
| 1234 | .br
|
|---|