GREP(1)
NAME
grep − search a file for a pattern
SYNOPSIS
grep [ option ... ] pattern [ 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 interpretation. 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 argument.)
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.
Plan 9 — September 20, 2000