runCommand -package:wai-app-static -package:libmpd -package:pandoc-plot -package:shake is:exact -package:process -package:mongoDB -package:options -package:io-streams -package:hledger -package:cabal-install

Run a Command.
Run an external command on the specified DotRepr. Remember to use hSetBinaryMode on the Handle for the output function if necessary. If the command was unsuccessful, then a GraphvizException is thrown. For performance reasons, a temporary file is used to store the generated Dot code. As such, this is only suitable for local commands.
Given a list of command/action pairs, prompt the user to choose a command using dmenu and return the corresponding action.