term% cat index.txt GREP(1) General Commands Manual GREP(1)
NAME
grep - search a file for a pattern
SYNOPSIS
grep [ -bchiLlnsv ] [ -e ] pattern | -f patternfile [ file ... ]
DESCRIPTION
Grep searches the input files (standard input default) for lines that
match the pattern, a regular expression as defined in regexp(6) with
the addition of a newline character as an alternative (substitute for
|) with lowest precedence. Normally, each line matching the pattern is
`selected', and each selected line is copied to the standard output.
The options are
-c Print only a count of matching lines.
-h Do not print file name tags (headers) with output lines.
-e The following argument is taken as a pattern. This option makes
it easy to specify patterns that might confuse argument parsing,
such as -n.
-i Ignore alphabetic case distinctions. The implementation folds
into lower case all letters in the pattern and input before in‐
terpretation. Matched lines are printed in their original form.
-l (ell) Print the names of files with selected lines; don't print
the lines.
-L Print the names of files with no selected lines; the converse of
-l.
-n Mark each printed line with its line number counted in its file.
-s Produce no output, but return status.
-v Reverse: print lines that do not match the pattern.
-f The pattern argument is the name of a file containing regular
expressions one per line.
-b Don't buffer the output: write each output line as soon as it is
discovered.
Output lines are tagged by file name when there is more than one input
file. (To force this tagging, include /dev/null as a file name argu‐
ment.)
Care should be taken when using the shell metacharacters $*[^|()=\ and
newline in pattern; it is safest to enclose the entire expression in
single quotes '...'. An expression starting with '*' will treat the
rest of the expression as literal characters.
SOURCE
/sys/src/cmd/grep
SEE ALSO
ed(1), awk(1), sed(1), sam(1), regexp(6)
DIAGNOSTICS
Exit status is null if any lines are selected, or non-null when no
lines are selected or an error occurs.
GREP(1)