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From: guy@gorodish.UUCP
Newsgroups: comp.unix.questions
Subject: Re: SCCS vs. RCS
Message-ID: <39814@sun.uucp>
Date: 23 Jan 88 23:40:22 GMT
References: <720003@hpclskh.HP.COM> <580@dsacg3.UUCP> <377@mks.UUCP> <163@teak.athertn.Atherton.COM>
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> There are many various versions of "diff" available; some hacking is
> required to make any suitable for use in RCS, but it is apparently not
> necessary.

The 4.3BSD version of "diff" (which is derived from AT&T code, and thus would
require an AT&T license unless they truly *have* abandoned any claim to
ownership) has had all the changes made to "diff" for RCS folded into it.  This
version is provided with a number of UNIX systems; for instance, SunOS provides
it with release 3.2 and all subsequent releases.

The main such change was the addition of the "-n" flag.  Check your man page;
if a "-n" flag is listed and described in terms such as "produce(s) a script
similar to that of '-e', but in the opposite order and with a count of changed
lines on each insert or delete command", you probably have the 4.3BSD version.

> I don't know any more (yet) about it.  We are looking into version 4,
> and I'll post something when I do have more to say about it.

Version 4 incorporates:

	1) the changes made by Jay Lepreau, which are in the version that came
	   with 4.3BSD, to make "rcsdiff" support all the options that the
	   4.3BSD "diff" does (including options such as the new "-w" and "-i"
	   options);

	2) changes to make it pass "lint" with many fewer complaints, so it can
	   work on e.g. systems with 16-bit "int"s and 32-bit pointers;

	3) changes to make it work on S3/S5 systems (although you'll have to
	   dig up a modified "diff" for many of those systems);

	4) changes to make it work on systems that disallow dereferencing null
	   pointers;

	5) a number of bug fixes.

I don't know what else it has.  I don't know what the arrangements are for
getting Version 4, but if you can get it, you probably should do so.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com