Anything that supports pipes and signals, and is easy to install. I've started using Steel Bank Common Lisp (SBCL) because it's the default implementation used with the Roswell installer.

https://github.com/roswell/roswell

(As a side-note: Perl 5 was really the ideal language for this, by design; we might be in a different world today if it hadn't been derailed by Perl Forever^W 6).

If I was ever to be religious, I would believe that PHP was the work of the devil. It's just so... uuuugh. It doesn't make sense. Did you know that you can increment a string in PHP? Yup. Of course you can't decrement it, that's crazy talk.

Anyway, I usually avoid perl. While definitely a true programming language, I really don't like it. I find that it lacks clarity, and quickly collapses into bash-like hackery.

I personally use Python when it's a notch above shell, but not enough to pull out the big guns.

(I use to write a lot of perl when I was a kid, even made an accounting system in it, so my dislike of perl is from experience. We also had a 6000 line perl build script at my current job which was the last drop. Rewrote it to 40 lines of batch and 150 lines of Python. Likewise, I also wrote a lot of PHP, and can no longer consider it a proper programming language.)