UNIX for Dummies Questions & Answers

Which languages would, in the long run, be best to learn on a UNIX environment
for kernel work, every day programs, and overall UNIX programming? I've been learning C for over a year now (which I'm pretty confident with) and decided I want to look into some other languages.

I'll mainly be working on UNIX-flavors like Linux. I've heard of sh (already know), PERL, Python, Ruby, Tcl, AWK, and some others. Which languages would be best
to learn? I know best is a pretty loose term in programming; I mean most important in UNIX, most useful. May not of made myself clear enough.

Any advice will be appreciated.

I have found Korn shell and AWK to give me most of what I need from a scripting standpoint. I also use Java when I need more.