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From: shannon@sun.UUCP
Newsgroups: net.unix,net.unix-wizards
Subject: Re: sh changes
Message-ID: <4230@sun.uucp>
Date: Thu, 19-Jun-86 01:58:54 EDT
Article-I.D.: sun.4230
Posted: Thu Jun 19 01:58:54 1986
Date-Received: Sat, 21-Jun-86 08:28:24 EDT
References: <18951@rochester.ARPA>
Organization: Sun Microsystems, Inc.
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> 
> I hit an incompatability between the 4.2 BSD sh and Sun 3.0 sh. Here
> are the relevant parts of the manual pages:
> 
>	...
> 
> In case you missed it, the difference is the extra colon in the Sun 3.0
> system. Questions: when and why was this change made?  Are there any
> other variants of Unix with this change? Has anybody's command file
> broken on account of this?
> 
> 	Ken
> -- 
> UUCP: ..!{allegra,decvax,seismo}!rochester!ken ARPA: ken@rochester.arpa
> Snail: CS Dept., U. of Roch., NY 14627. Voice: Ken!

A few lines down on the same Sun 3.0 man page:

	"If the colon (:) is omitted from the above expressions,
	the shell only checks whether parameter is set or not."

I believe there is no incompatibility.

The Sun 3.0 sh is based on the System V sh, unlike the 4.xBSD sh,
which is based on the V7 sh.  The System V sh has fixed a number
of bugs and is overall much more reliable.

					Bill Shannon