GREP(1) 						      General Commands Manual							   GREP(1)

NAME

       grep, egrep, fgrep - search a file for a pattern

SYNOPSIS

       grep [ option ] ...  expression [ file ] ...

       egrep [ option ] ...  [ expression ] [ file ] ...

       fgrep [ option ] ...  [ strings ] [ file ]

DESCRIPTION

       Commands  of  the  grep	family search the input files (standard input default) for lines matching a pattern.  Normally, each line found is
       copied to the standard output.  Grep patterns are limited regular expressions in the style of ex(1); it	uses  a  compact  nondeterministic
       algorithm.   Egrep  patterns  are  full regular expressions; it uses a fast deterministic algorithm that sometimes needs exponential space.
       Fgrep patterns are fixed strings; it is fast and compact.  The following options are recognized.

       -v     All lines but those matching are printed.

       -x     (Exact) only lines matched in their entirety are printed (fgrep only).

       -c     Only a count of matching lines is printed.

       -l     The names of files with matching lines are listed (once) separated by newlines.

       -n     Each line is preceded by its relative line number in the file.

       -b     Each line is preceded by the block number on which it was found.	This is sometimes useful in locating disk block  numbers  by  con-
	      text.

       -i     The  case  of  letters  is ignored in making comparisons -- that is, upper and lower case are considered identical.  This applies to
	      grep and fgrep only.

       -s     Silent mode.  Nothing is printed (except error messages).  This is useful for checking the error status.

       -w     The expression is searched for as a word (as if surrounded by `<' and `>', see ex(1).)	(grep only)

       -e expression
	      Same as a simple expression argument, but useful when the expression begins with a -.

       -f file
	      The regular expression (egrep) or string list (fgrep) is taken from the file.

       In all cases the file name is shown if there is more than one input file.  Care should be taken when using the characters $ * [ ^ | ( ) and
        in the expression as they are also meaningful to the Shell.  It is safest to enclose the entire expression argument in single quotes ' '.

       Fgrep searches for lines that contain one of the (newline-separated) strings.

       Egrep accepts extended regular expressions.  In the following description `character' excludes newline:

	      A  followed by a single character other than newline matches that character.

	      The character ^ matches the beginning of a line.

	      The character $ matches the end of a line.

	      A .  (period) matches any character.

	      A single character not otherwise endowed with special meaning matches that character.

	      A  string  enclosed in brackets [] matches any single character from the string.	Ranges of ASCII character codes may be abbreviated
	      as in `a-z0-9'.  A ] may occur only as the first character of the string.  A literal - must be placed where it can't be mistaken	as
	      a range indicator.

	      A  regular  expression  followed	by  an	* (asterisk) matches a sequence of 0 or more matches of the regular expression.  A regular
	      expression followed by a + (plus) matches a sequence of 1 or more matches of the regular expression.  A regular expression  followed
	      by a ? (question mark) matches a sequence of 0 or 1 matches of the regular expression.

	      Two regular expressions concatenated match a match of the first followed by a match of the second.

	      Two regular expressions separated by | or newline match either a match for the first or a match for the second.

	      A regular expression enclosed in parentheses matches a match for the regular expression.

       The order of precedence of operators at the same parenthesis level is [] then *+? then concatenation then | and newline.

       Ideally there should be only one grep, but we don't know a single algorithm that spans a wide enough range of space-time tradeoffs.

SEE ALSO

       ex(1), sed(1), sh(1)

DIAGNOSTICS

       Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or inaccessible files.

BUGS

       Lines are limited to 256 characters; longer lines are truncated.

4th Berkeley Distribution					  April 29, 1985							   GREP(1)