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EGREP(1)							      EGREP(1)

NAME    [Toc]    [Back]

     egrep - search a file for a pattern using full regular expressions

SYNOPSIS    [Toc]    [Back]

     egrep [options] full regular expression [file ...]

DESCRIPTION    [Toc]    [Back]

     egrep (expression grep) searches files for	a pattern of characters	and
     prints all	lines that contain that	pattern.  egrep	uses full regular
     expressions (expressions that have	string values that use the full	set of
     alphanumeric and special characters) to match the patterns.  It uses a
     fast deterministic	algorithm that sometimes needs exponential space.

     egrep accepts full	regular	expressions as in ed(1), except	for \( and \),
     and except	for \< and \>, with the	addition of:

     1.	   A full regular expression followed by + that	matches	one or more
	   occurrences of the full regular expression.
     2.	   A full regular expression followed by ? that	matches	0 or 1
	   occurrences of the full regular expression.
     3.	   Full	regular	expressions separated by | or by a new-line that match
	   strings that	are matched by any of the expressions.
     4.	   A full regular expression that may be enclosed in parentheses ()
	   for grouping.

     Be	careful	using the characters $,	*, [, ^, |, (, ), and \	in full
     regular expression, because they are also meaningful to the shell.	 It is
     safest to enclose the entire full regular expression in single quotes

     The order of precedence of	operators is [], then *?+, then	concatenation,
     then | and	new-line.

     If	no files are specified,	egrep assumes standard input.  Normally, each
     line found	is copied to the standard output.  The file name is printed
     before each line found if there is	more than one input file.

     Command line options are:

     -b	   Precede each	line by	the block number on which it was found.	 This
	   can be useful in locating block numbers by context (blocks are 512
	   bytes long and number from 0).
     -c	   Print only a	count of the lines that	contain	the pattern.
     -h	   Suppresses printing of filenames when searching multiple files.
     -i	   Ignore upper/lower case distinction during comparisons.
     -l	   Print the names of files with matching lines	once, separated	by
	   new-lines.  Does not	repeat the names of files when the pattern is
	   found more than once.
     -n	   Precede each	line by	its line number	in the file (first line	is 1).
     -s	   Silent mode.	 No pattern matches or error messages are printed.
	   This	option allows command expressions to check egrep's exit	status
	   without having to deal with output.

									Page 1

EGREP(1)							      EGREP(1)

     -v	   Print all lines except those	that contain the pattern.
     -e	special_expression
	   Search for a	special	expression (full regular expression that
	   begins with a -).
     -f	file
	   Take	the list of full regular expressions from file.

SEE ALSO    [Toc]    [Back]

     ed(1), fgrep(1), grep(1), sed(1), sh(1).

DIAGNOSTICS    [Toc]    [Back]

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

BUGS    [Toc]    [Back]

     Ideally there should be only one grep command, but	there is not a single
     algorithm that spans a wide enough	range of space-time tradeoffs.	Lines
     are limited to BUFSIZ characters; longer lines are	truncated.  BUFSIZ is
     defined in	/usr/include/stdio.h.

									PPPPaaaaggggeeee 2222
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