I have a method that works for this kind of thing. I press alt-star at an empty bash prompt. That combination lists every possible tab-expansion at where the cursor is, so at an empty prompt it lists all commands (including builtins, aliases, and shell functions). Then I press control-A to go to the beginning and type 'echo >a' -- I have to do this blindly because readline only displays the last screenful of the command line correctly, but that doesn't really matter. Then I type enter. This saves the lists of all commands to a temp file. Then I can search this file with a simple command like tr \  \\n <a | grep foo or something.