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From: larry@kitty.UUCP
Newsgroups: net.micro.att
Subject: Re: UNIX PC command surprises...
Message-ID: <919@kitty.UUCP>
Date: Fri, 28-Mar-86 11:30:56 EST
Article-I.D.: kitty.919
Posted: Fri Mar 28 11:30:56 1986
Date-Received: Tue, 1-Apr-86 07:15:25 EST
References: <351@hropus.UUCP> <888@kitty.UUCP> <2012@brl-smoke.ARPA>
Organization: Recognition Research Corp., Clarence, NY
Lines: 34
Summary: Well, the 7300 has DEPARTED from System V Release 2

In article <2012@brl-smoke.ARPA>, gwyn@brl-smoke.ARPA (Doug Gwyn ) writes:
> In article <888@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
> > In article <351@hropus.UUCP>, jrw@hropus.UUCP (Jim Webb) writes:
> > > 	Has anyone else out there noticed that on the "7300" the
> > > 	grep, egrep, and fgrep commands are IDENTICAL.  The other
> > > 	day I did an egrep "nproc|NPROC" or some such thing and
> > > 	it failed!  A quick cmp of grep and egrep yielded no 
> > > 	differences, in fact, grep and fgrep are linked together.
> >
> >	In case you still don't know the answer...  In an program, argv[0] is
> >the NAME by which the program was invoked. Since the source code for grep and
> >egrep is very similar, the same compiled program is used, with the argv[0]
> >being used to switch the internal program logic.  The same situation is also
> >used for the above editors.
> 
> What makes you think the source code for grep & egrep is similar?
> They haven't been at all similar from the beginning through SVR2.

	Traditional System V Release 2.x does use two totally different
programs for egrep(1) and grep(1).  In fact, while the grep source is simply
grep.c, the egrep source is egrep.y which uses a deterministic algorithm as
produced by yacc.
	HOWEVER, this is NOT TRUE FOR THE 7300; the 7300 functions are
identical!  I don't have specific source code for the 7300, so I don't know
what algorithm is used for the grep functions, but it is obviously not the
same as traditional Sys V Release 2.  I have no idea why AT&T has made this
departure for the 7300.

==>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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