- Add missing 'shift' in --list case (caused infinite loop)
- Initialize color vars to empty strings before tput block
(set -u errored when tput unavailable or non-TTY)
Usage: docker-stacks-update -s stack_a -s stack_b
Only matching running stacks are processed. Shows a helpful message
with available stacks if no match is found.
- Add -h/--help usage with options
- Add argument parsing with unknown-option error
- Fix update detection: 'Pulled' appears for all services even when
up-to-date; only 'Downloaded newer image for' is reliable
jeremy