I'm in agreement with the poster. Even while it's useful one for people to know, it's not a easy command to find though, is it? I've been putting my xmodmap entries into "~/.Xmodmap" in Ubuntu, it seems to reload it fine on restart of X.
Not sure if anyone cares but I've mapped my Tab to Esc and Caps Lock to Tab. Makes vi easier to use, especially on those laptops that have that microscopic escape key in the upper left. Here's my
remove lock = Caps_Lock
keycode 23 = Escape
keycode 66 = Tab