-s (silent) is also undocumented. There's a confusing distinction between it and -q (quiet), where the latter isn't quiet in the usual sense; -s is needed to silence non-error output entirely. There's useless output even when called entirely without options:
$ pngcrush CPU time decode 0.000000, encode 0.000000, other 0.000000, total 0.000002 sec $ pngcrush -q CPU time decode 0.000000, encode 0.000000, other 0.000000, total 0.000002 sec $ pngcrush -s $ This is pngcrush 1.8.13-0.1 on focal. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1593645 Title: manpage does not document "-reduce" parameter To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pngcrush/+bug/1593645/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs