usage: send file(s):               xx [:slot] file...
   or: send STDIN:                 xx [:slot] -
   or: send pipe:                  ... | xx [:slot]
   or: get file(s) or STDIN:       xx [:slot]
   or: get file(s) no-questions:   xx [:slot] --
examples: dmesg | xx
          xx project
          xx --
          xx :conf /etc /boot

See also use case