topic Re: Shell Question. in Operating System - HP-UX

Shell Question.

joe_91 — Mon, 12 Aug 2002 23:15:37 GMT

Hi:

One of my developers has written a script that would run as /sbin/sh. Is this not the root's shell?? Would there be any disadvantages of that approach? Please Advise.

Thanks
Joe.

Re: Shell Question.

harry d brown jr — Mon, 12 Aug 2002 23:36:24 GMT

(1) /sbin/sh is not just a shell used by root, any "normal" user could use it.

(2) real developers don't use "sh", they code in perl :-)))))

live free or die
harry

Re: Shell Question.

A. Clay Stephenson — Tue, 13 Aug 2002 01:07:55 GMT

/sbin/sh is still the POSIX shell and is just as functional as /usr/bin/sh; the difference is that /sbin/sh is statically linked and thus will run before shared libraries (e.g. /usr/lib/xxx) become available in single-user mode. The version in /usr/bin uses shared libries and is thus more memory efficient. The /usr/bin version is the one that should be used unless this script needs to run before /usr is mounted. Many people mistakenly believe that /sbin/sh is the Bourne shell but that is not the case.

Re: Shell Question.

Don Spare — Tue, 13 Aug 2002 11:49:18 GMT

I think a bigger question is why a developer would want to do this in the first place? If he is trying to implement some sort of startup shell there are better ways to do it than to replace the basic system software, for example, modify users .profile to run the new shell would be my choice.

I would suggest that you have the developer find a different way.

Re: Shell Question.

joe_91 — Tue, 13 Aug 2002 14:31:35 GMT

Hi:

Are they any disadvantages of using /sbin/sh?

Thanks
Joe.

Re: Shell Question.

Pete Randall — Tue, 13 Aug 2002 14:33:45 GMT

As Clay pointed out, the version in /usr/bin is more memory efficient. Other than that, I can't think of any disadvantage.

Pete

Re: Shell Question.

Sajid_1 — Tue, 13 Aug 2002 14:35:19 GMT

hello,

This document may explain you better - http://support2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000060946454

Doc ID - A5804466B

Re: Shell Question.

H.Merijn Brand (procura — Tue, 13 Aug 2002 14:35:20 GMT

... other reason: portability

/usr/bin/sh can be found on any modern unix system, /sbin/... is local to the OS vendor

Re: Shell Question.

James R. Ferguson — Tue, 13 Aug 2002 14:36:48 GMT

Hi Joe:

Clay has already provided the answer to your last question: "The version in /usr/bin uses shared libraries and is thus more memory efficient."

Generally one should use the version in '/usr/bin' for this reason, unless you have scripts that will run in situations where '/usr' isn't mounted (also noted above in earlier posts).

Beyond these guidelines, the choice is really yours. However, do *not* change the default shell of 'root'!!! It must be '/sbin/sh' for a bootable system!!!

Regards!

...JRF...