Shell Script Question

[Brad De Vries]

On 6/1/05, David Bandel <david.bandel at gmail.com> wrote:
> Wonder why this reply didn't go to the list?
>
> On 6/1/05, Alma J Wetzker <almaw at ieee.org> wrote:
> > I don't do much scripting beyond expect, can you have more than one
> > return value to a script?  I counted three desired variables.  Is there
> > a way to get all three out without going to global?
> >
> > In C, I would pass two by reference and return the third.  Can you do
> > weird stuff like that in a script?
> 
> Good question.  And the answer is:  I don't have a clue.  And it could
> be different between ksh, bash, bash2, and bash3.  As soon as
> something really needs more than very simple scripting, I drop into
> Perl mode.  In Perl I can pass several variables to a subroutine, no
> reference needed (although Perl can do all those memory tricks of
> passing a memory address of a variable).  And there are ways to get
> them back out, too.
> 
> Brad, what shell are you calling and have you tried calling a
> different one?  Last time I worked on AIX and HP-UX, they didn't have
> bash.  They had borne and korn shells and that was about it (unless
> you liked to abuse yourself with a C-shell -- which should only be
> sold down by the sea shore).
> 
> Ciao,
> 
> David A. Bandel

I use the bourne shell (#!/bin/sh) for virtually all my scripts
because I deal with several UNIX variants (including cygwin and MKS
Toolkit, UNIX environments on Windows.)  I would love to use perl for
many of my projects but I can't always guarantee that it will be
installed and trying to get a sys-admin to install perl when they've
gone without it for 10+ years is a little like trying to push a rope. 
Sadly I don't push too hard because I know shell scripting but my perl
skills are pretty weak.

I would guess that 90-95% of all my scripts work perfectly everywhere
I go with the one big exception of this looping issue.  Stuff I wrote
in the late 80's worked this way and when I started working with Linux
and bash I found it worked differently.  Now I know why.

To answer Alma's question about passing variables by reference, I'd
have to say that the shell does not have that ability.  Actually,
until I started working with AIX and ksh, I'd never even heard of that
concept of local variables in shell scripts.  Ksh and bash, there may
be others, allow the you to define local variables but in sh and csh
every variable that you create is global.

Brad.