sh changes

[shannon at sun.UUCP]

> 
> 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 at 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