#! /bin/bash
exec $(echo ${0##*/} | tr ':' '/')
and save the file named, say, ls /Users/paul. After quitting the editor, in a Terminal window, do a: % chmod +x ls\ \:Users\:pjl(Mac OS X substitutes colons for slashes in the Terminal, and they need to be escaped with backslashes)
In the Finder, do a Get Info on the file and change the Open With application to Terminal. Now double-clicking the file in the Finder will create a new Terminal window and run the command ls /Users/paul in it.
If you want to change the command, simply rename the file in the Finder. I use this for ssh machine so I can ssh to various machines. If you want several such commands, simply duplicate the file in the Finder and rename it. The contents of the file never need to change.

