Bash is more commonly widespread but some systems use old bash in the enterprise realm.
But LISP is good. If you want to get into something that is also good for scripting, look into LUA. It just makes sense (to me at least). But I had been getting back into bash because, not all sites support perl and perl gets just as bad of a rap as ruby. I am versed in all of the old tools that still make the world go round. As a result, by bash-fu has a lot of perl for ease us string manipulation. If you are using bash from the last 2 years, there have been some really good improvements to help with stuff like that so you don’t need to invoke sed or awk, but the syntax is a little head scratchy at times.