From: kagel AT quasar DOT bloomberg DOT com Date: Tue, 15 Oct 1996 19:24:37 -0400 Message-Id: <9610152324.AA03279@quasar.bloomberg.com > To: dj AT delorie DOT com Cc: djgpp AT delorie DOT com In-Reply-To: <199610152304.TAA14292@delorie.com> (message from DJ Delorie on Tue, 15 Oct 1996 19:04:02 -0400) Subject: Re: GREP Reply-To: kagel AT dg1 DOT bloomberg DOT com Errors-To: postmaster AT bloomberg DOT com Date: Tue, 15 Oct 1996 19:04:02 -0400 From: DJ Delorie Cc: djgpp AT delorie DOT com Content-Type: text Content-Length: 373 > I won't repeat the descriptions but GREP stands for: > "Global Regular Expression Print" > EGREP: Extended Global Regular Expression Print > FGREP: Fast Global Regular Expression Print Sorry, *File* Global Regular Expression Print. fgrep accepts a file of expressions to search for. egrep is, traditionally, the fastest of the three, with fgrep being the slowest. From the System V.4 man page: NAME fgrep - search a file for a character string SYNOPSIS fgrep [options] string [file ...] DESCRIPTION fgrep (fast grep) searches files for a character string and prints ^^^^^^^^^ [SNIP] Fgrep is Fast GREP because it does not accept regular expressions only strings, and because it precompiles the list of strings into a data structure which permits its search time to be independent of the length of the search list and so is far faster. While egrep and some modern grep implementations perform similar optimizations the original grep did not, hence fgrep. So, actually, in my haste to reply I was wrong but you are not correct. By the way some sources, including the System V.4 man pages, also call EGREP Expression GREP. In a sense either Extended GREP or Expression GREP is at least descriptive as the difference between grep and egrep is that grep accepts "Limited Regular Expressions" while egrep accepts "Extended Regular Expressions". Taking a file of expressions to match is also an egrep feature, BTW. Not to have the last word but this is wnough off topic stuff for the list/group. Anyone interested in continuing the discussion can email directly and I will try to CC: all interested parties. -- Art S. Kagel, kagel AT dg1 DOT bloomberg DOT com A proverb is no proverb to you 'till life has illustrated it. -- John Keats