Re: [tlug] displaying executed commands in shell scripts

["Stephen J. Turnbull" <stephen@example.com>]

Arwyn Hainsworth writes:

 > Eh? I thought bash was POSIX-compliant.

Not quite.  You can run the scripts, but there are cases where Bash
gives different results unless POSIXLY_CORRECT=t is in the
environment.  Also, Bash is supposed to behave as a pure POSIX shell
when invoked as sh, but basically that has always been a lie; every
version fixes some incompatibilities and adds new ones.

 > Also Ubuntu uses Dash for it's /bin/sh, not Korn. IIRC ksh, like bash, is
 > POSIX + extras. It just has different extras to bash.

That's true for pdksh.  I think that the original ksh is quite close
to POSIX, though, and I believe Bash claims to be nearly a superset of
original ksh.

 > The reason Ubuntu uses dash is due to it being POSIX-only and thus
 > having a low overhead and being a lot faster than the rest.

I think Ubuntu uses it because Debian does, actually. :-)