runCommand -package:options -package:shake -package:shake-plus -is:exact package:xmonad-contrib -is:exact

Given a list of command/action pairs, prompt the user to choose a command using dmenu and return the corresponding action.
Given the name of a command from defaultCommands, return the corresponding action (or the null action if the command is not found).
Given a list of command/action pairs, prompt the user to choose a command using dmenu-compatible launcher and return the corresponding action. See X.U.Dmenu for compatible launchers.