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Top Forums Shell Programming and Scripting Understanding regex behaviour when using quantifiers Post 302750267 by DGPickett on Monday 31st of December 2012 09:56:37 AM
Old 12-31-2012
This is shorter: Regular expression - Wikipedia, the free encyclopedia

QED went to MULTICS, probably before UNIX, and became qedx, which is very close to ed and ex. Later, Waterloo ported it to FRED.

grep -E is essentially egrep is ERE.
 

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ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME
zgrep - search possibly compressed files for a regular expression SYNOPSIS
zgrep [ grep_options ] [ -e ] pattern filename... DESCRIPTION
Zgrep is used to invoke the grep on compress'ed or gzip'ed files. All options specified are passed directly to grep. If no file is speci- fied, then the standard input is decompressed if necessary and fed to grep. Otherwise the given files are uncompressed if necessary and fed to grep. If zgrep is invoked as zegrep or zfgrep then egrep or fgrep is used instead of grep. If the GREP environment variable is set, zgrep uses it as the grep program to be invoked. For example: for sh: GREP=fgrep zgrep string files for csh: (setenv GREP fgrep; zgrep string files) AUTHOR
Charles Levert (charles@comm.polymtl.ca) SEE ALSO
grep(1), egrep(1), fgrep(1), zdiff(1), zmore(1), znew(1), zforce(1), gzip(1), gzexe(1) ZGREP(1)
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