Apparently this isn't well supported by dash, which will print an
error and return a 2, where zsh and bash will return 255.
Explicitly returning 255 seems least surprising.
see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=772322
#IHaveNoIdeaWhatThisScriptDoes
echo "-no-raw Do NOT allow images to be zero compression"
echo "-min-quality VAL Do NOT allow lossy images with quality < VAL (0-100)"
echo "-max-quality VAL Do NOT allow lossy images with quality > VAL (0-100)"
- exit -1
+ exit 255
}
if [ $# -lt 1 ]; then