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Unix Version 7 - man page for grep (v7 section 1)

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GREP(1) 										  GREP(1)

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

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

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

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

       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;  unless
       the -h flag is used, the file name is shown if there is more than one input file.

       Grep  patterns  are  limited  regular expressions in the style of ed(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.

       -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 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 context.

       -s     No output is produced, only status.

       -h     Do not print filename headers with output lines.

       -y     Lower  case  letters in the pattern will also match upper case letters in the input
	      (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.

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

       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 matches that character.

	      The character ^ ($) matches the beginning (end) of a line.

	      A .  matches any character.

	      A single character not otherwise endowed with special meaning matches that  charac-

	      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 * (+, ?) matches a sequence of 0  or  more  (1  or
	      more, 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

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

       ed(1), sed(1), sh(1)

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

       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.

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

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