ultrix sh "set -r" (was Re: Restricted shell)

[Mike Khaw]

<278 at dcs.UUCP>, by wnp at dcs.UUCP (Wolf N. Paul):
> In article <901 at philmds.UUCP> leo at philmds.UUCP (Leo de Wit) writes:
>>I'm interested both in what restriction means in System V, and whether
>>there is any documentation about -r (set -r, sh -r) for the BSD /bin/sh.
>>Furthermore I'm interested in hearing about its use (for what, and how).
...
> Some notes: sh and rsh are links to the same binary, with "sh -r" being 
> equivalent to an invocation of rsh. "set -r" after the shell has started
> also has the same effect, as Leo's demo showed. The manual further points out

With regard to Ultrix, in version 2.2 /bin/sh is mostly the Berkeley
flavor, while the System V flavors are /bin/sh5 and /bin/rsh5, both of
which are symbolic links to /usr/bin/sh5.

That Ultrix's /bin/sh supports "set -r" may be because it's a DEC addition
for System V compatibility -- anyone from DEC care to comment?  By way
of comparison, neither SunOS 3.5 nor SunOS 4.0 /bin/sh support "set -r".
Sun's /bin/sh looks at the SHELL env. var. to begin with "r" to decide to
run a restricted shell.

Mike Khaw
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