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.
unique -V (return code: 1)
open: version: File exists
unique (return code: 0)
Usage: unique OUTPUT-FILE