Note: help and version output are generated by a naïve script which tries a few variants of
<command> --help, <command> -h etc. to find the command's help and version info.
Sometimes it gets lucky, sometimes it doesn't; if the output below looks wrong, it probably is.
tmux -VERSION (return code: 0)
tmux 2.1
tmux --help (return code: 1)
usage: tmux [-2CluvV] [-c shell-command] [-f file] [-L socket-name]
[-S socket-path] [command [flags]]