What would I be looking for? I of course checked perldoc before asking my question. As near as I can see, I have passed the arguments correctly.

If you mean that I should pass the arguments in an array, I have tried passing arguments as an array but this made no difference: the directories were included in the zip file.

@zipcommand = ("/usr/bin/zip", "-D", "$zipfile",  "$somepath/*.$fileex
+t");
[download]

Moreover, when I use the array method, zip interprets the commandline redirects as filenames and cannot match the files if $fileext is a glob pattern like "*.jpg".