grep, egrep, fgrep, zgrep, zegrep, zfgrep - file pattern
searcher
grep [-AB num] [-CEFGHILPRSUVZabchilnoqsvwx]
[--context[=num]]
[--binary-files=value] [--line-buffered] [-e pattern]
[-f file]
[pattern] [file ...]
The grep utilities search the given input files selecting
lines that
match one or more patterns. By default, a pattern matches
an input line
if any regular expression (RE) in the pattern matches the
input line
without its trailing newline. An empty expression matches
every line.
Each input line that matches at least one of the patterns is
written to
the standard output.
The grep utility is used for simple patterns and ex(1) or
ed(1) style
regular expressions. The egrep utility can handle extended
regular expressions
and multi-line patterns. The fgrep utility is
quick but can
handle only fixed patterns consisting of one or more lines,
allowing any
of the pattern lines to match a portion of the input. The
zgrep, zegrep,
and zfgrep utilities act like grep, egrep, and fgrep respectively but accept
input files compressed with the compress(1) or gzip(1)
compression
utilities.
The following options are available:
-A num Print num lines of trailing context after each
match.
-B num Print num lines of leading context before each
match.
-C Print 2 lines of leading and trailing context after
each match.
Equivalent to -A 2 -B 2.
-E Force grep to behave as egrep.
-F Force grep to behave as fgrep.
-G Force grep to behave as grep.
-H If -R is specified, follow symbolic links only if
they were explicitly
listed on the command line.
-I Ignore binary files.
-L Only the names of files not containing selected
lines are written
to standard output. Pathnames are listed once per
file searched.
If the standard input is searched, the pathname `-'
is written.
-P If -R is specified, no symbolic links are followed.
-R Recursively search subdirectories listed.
-S If -R is specified, all symbolic links are followed.
-U Search binary files, but do not attempt to print
them.
-V Display version information.
-Z Force grep to behave as zgrep.
-a Treat all files as text.
-b The offset in bytes of a matched pattern is displayed in front of
the respective matched line.
-c Only a count of selected lines is written to standard output.
-e expression
Specify a pattern used during the search of the input. Multiple
-e options can be used to specify multiple patterns;
an input
line is selected if it matches any of the specified
patterns.
-f pattern_file
Read one or more newline separated patterns from
pattern_file.
Newlines are not considered part of a pattern.
-h Never print filename headers with output lines.
-i Perform case insensitive matching.
-l Only the names of files containing selected lines
are written to
standard output. Pathnames are listed once per file
searched.
If the standard input is searched, the pathname `-'
is written.
-n Each output line is preceded by its relative line
number in the
file, starting at line 1. The line number counter
is reset for
each file processed. This option is ignored if -c,
-l, or -q is
specified.
-o Always print filename headers with output lines.
-q Suppress normal output.
-s Silent mode. Nonexistent and unreadable files are
ignored.
-v Selected lines are those not matching any of the
specified patterns.
-w The expression is searched for as a word (as if surrounded by
`[[:<:]]' and `[[:>:]]', see re_format(7)).
-x Only input lines selected against an entire fixed
string or regular
expression are considered to be matching lines.
--context[=num]
Print num lines of leading and trailing context.
Default is 2.
--binary-files=value
Controls searching and printing of binary files.
Options are
binary, the default, search binary files but do not
print them;
without-match, do not search binary files; and text,
treat all
files as text.
--line-buffered
Force output to be line buffered. By default, output is line
buffered when standard output is a terminal and
block buffered
otherwise.
If no file arguments are specified, the standard input is
used.
The grep utility exits with one of the following values:
0 One or more lines were selected.
1 No lines were selected.
>1 An error occurred.
EXTENDED REGULAR EXPRESSIONS [Toc] [Back] The following characters are interpreted by egrep:
$ Align the match from the end of the line.
^ Align the match from the beginning of the line.
| Add another pattern (see example below).
? Match 1 or less sequential repetitions of the pattern.
+ Match 1 or more sequential repetitions of the pattern.
* Match 0 or more sequential repetitions of the pattern.
{} Match specified number of sequential repetitions of
the pattern.
[] Match any single character or range of characters enclosed in the
brackets.
Escape special characters which have meaning to egrep,
the set of
`$.^[]|?+*{}()'.
To find all occurrences of the word patricia in a file:
grep patricia myfile
To find all occurrences of the pattern `.Pp' at the beginning of a line:
grep '^.Pp'
The apostrophes ensure the entire expression is evaluated by
grep instead
of by the user's shell. The caret `^' matches the null
string at the beginning
of a line, and the `' escapes the `.' which would
otherwise
match any character.
To find all lines in a file which do not contain the words
foo or bar:
grep -v -e foo -e bar myfile
A simple example of an extended regular expression:
egrep '19|20|25' calendar
Peruses the file calendar looking for either 19, 20 or 25.
ed(1), ex(1), sed(1), regex(3), regexp(3), re_format(7)
The grep command appeared in Version 6 AT&T UNIX.
OpenBSD 3.6 July 3, 1999
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