adding commands?
 

Is there a way to assign new commands to software, say for instance if I'd like to start xmms by hitting Alt+F2 and typing "music" instead of "xmms"
or if you install new software without a command and want to assign it your own one?

Use the alias command. I'm not a slack user but for Mandrake I add them to the users .bashrc file. It is hidden file located in the users home directory.

http://campuscgi.princeton.edu/man?alias#sect6
http://mirrors.ccs.neu.edu/cgi-bin/u...an-cgi?alias+1

If you mean Alt-F2 from a GUI (w/stock xmms, I assume so) your window manager should have some keyboard configuration capability. And yeah, either aliases in ~/.bashrc or symlinks, and so on.

What kind of software doesn't have a command, though? (That sentence hurts my head to even type.) That'd be a neat trick. :)