Readline and rlwrap
I came across a neat little tool called rlwrap, which essentially wraps the functionality of readline (line editing, history, etc) for any other command line utility. For example, it works well with my GCCalc hack, which I didn’t bother to integrate readline into, but rlwrap gives you the same thing for free:
rlwrap gccalc
It’s useful with many other tools, like telnet and netcat, and interactive interpreters that don’t have line editing or history, like Rhino (Javascript) and others.