This article is from a FAQ concerning SCO operating systems. While some of the information may be applicable to any OS, or any Unix or Linux OS, it may be specific to SCO Xenix, Open This is an old article about SCO Unix and is only left here for historical purposes. There is lots of Linux, Mac OS X and general Unix info elsewhere on this site: Search this site is the best way to find anything.
This is an ancient post with no relevance to modern systems.
This is probably NOT a good idea for several reasons.
First, you definitely cannot change it to csh, bash, or tcsh. If you do, startup scripts will fail spectacularly or mysteriously because they are written for /bin/sh and just plain will not work with those other shells.
You can probably change to ksh with no ill effects, but you are taking a small chance. The reason is that ksh has a lot more builtin functions, so if a script written for /bin/sh happened to define a function with the same name as a ksh builtin, that script would fail if run with /bin/ksh (again, mysteriously or spectatcularly depending on what the function does).
A cautious approach is to setup your environment (create /.kshrc and add the ENV setting to /.profile) for ksh and then just run "ksh" after logging in. You can do the same thing for any alternative shell you want to run. See /Unixart/ksh.html for more details on that.
A related issue is that of static linking. The shells you normally run are dynamically linked- that is, they depend on shared libraries (run "ldd /bin/sh" to see this). OSR5.0.5 and up provide static versions of a few utilities in /sbin that could be used in the event of damage to the shared libraries (which could be as simple as a lost symbolic link- see https://aplawrence.com/cgi-bin/ta.pl?arg=110334).
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