Shell Programming and Scripting

I am very new to Unix. I need to write a script that will grep some files, etc. When I write the script, do I need to know what shell I am using? If so, how do I do that?

Of course, as all shells use slightly different syntax, although can be generalised into two main categories, Bourne and C. There are several enhancements to the Bourne shell, notably ksh and bash (also sh-posix).

This thread explains the shebang line that goes at the top of your script and indicates which shell should be called to interpret your script.

You can find out which shell you're currently using via echo $SHELL (or if "echo $0" if SHELL isn't set). Of course, you can specify a different shell scripting language for your script.

Also, (my personal advice) is don't try to script using any form of the C shell, whoa no! Use ksh or bash if they're available.

Cheers
ZB