grep \- search a file for a pattern
] expression [ file ] ...
Normally, each line found
is copied to the standard output.
all lines but those matching
only a count of matching lines is printed.
only names of files which contain matching lines are printed.
flag is used, then case of letters is ignored in comparisons.
flag is used, then the expression is searched for as a word
(as if surrounded by `\e<' and `\e>',
its relative line number in the file.
each line is preceded by the block number
This is sometimes useful in locating
disk block numbers by context.
In all cases the file name is shown if there is more than one input file.
For a complete description
of the regular expressions,
Care should be taken when
$ * [ ^ | ( ) and \\ in the regular
also meaningful to the Shell.
It is generally necessary to enclose the
are limited to 256 characters;
longer lines are truncated.