How do I partially suppress the command-line output of zip?
Solution 1:
zip -q -T -m output *.png && echo "success" || echo "failure"
should work too, alternative to the solution, given in the comments.
It works like this: If the first commmand (zip ...) succeeds, the following combination with && can succeed too and is performed. But if the first part fails, then the whole combination will fail, and the &&-part is skipped, but an or-combination is successfull if one of both is successful, so the ||-part is performed.
You aren't interested in the combined result (true/false), but in the side-effect: a status feedback.
Solution 2:
Alternatively you can use pythons own zip library:
http://docs.python.org/library/zipfile.html