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.
/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.
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.
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!!!
