Im looking for a Reverse Polish Notation (RPN) calculator program for Linux. Must be programmable, im not too picky on the exact syntax of the language, as long as there is adequate instruction on its use (man page). Preferably something in the Ubuntu Repositories (or has a .deb for it). Any suggestions welcome!

Fedora has orpie. Never used it, but it's the only thing that comes up on a "yum search rpn". Description:
Edit: might be interesting to write your own, if you are so inclined.

You don't seem to require that it have a GUI, so sometimes the oldest is the best. It's called dc. It's beem part of the UNIX world longer than the C programming language has. These days, it's part of the bc package:

http://ftp.gnu.org/pub/gnu/bc/bc-1.06.tar.gz

It's so ancient and so classic that your distribution might already contain an executable for it. Try this at the command line:
Hope this helps.

dc is great, but I sure wish it had the basic transcendental functions. It integrates quite well with scripts.
Kevin Barry

Turns out i have dc already installed. Looked through the man pages and found a few things missing that i may require. Trigonometric functions being one of them. I will need to use exponents also. Possibly some basic matrices. Basically a fully functional engineering grade calculator. As far as the programming goes, i guess since it runs in the shell i would just need to write a script for automating arithmetic?

Edit: I also tried orpie, looks loaded with features, probably more than i need. Is it possible to write programs for it though?

I have actually written a basic command-line RPN calculator for fun in just about every language I learned!

As for GUI calculators, "Qalculate!" has a pretty good RPN mode.

I tried Qalculate, packed with features, quite impressive. Is it programmable?

I actually don't know what a programmable calculator is.

if you want there ARE the HP calc's for the desktop
http://freshmeat.net/projects/nonpareil/

i run a 11c on gnome

You might look at some of these:
http://www.hpcalc.org/hp48/pc/emulators/

Kevin Barry