runCommand -package:wai-app-static -package:libmpd -package:graphviz -package:structured-cli -package:shake-plus -package:process is:exact -package:options -package:github-release -package:io-streams -package:cabal-install -package:mongoDB -package:pandoc-plot -package:hledger

Run a Command.
Given a list of command/action pairs, prompt the user to choose a command using dmenu and return the corresponding action.