Thanks for the Capture::Tiny suggestion.

Actually, I just found a what seems to be unpublished option for GSUTIL that works for only the cp command. There is a -q switch. Why this isn't better documented, I don't know.

So, you can use this:

$cmd = "gsutil cp -q -a public-read $localfile gs://g3.mydomain.com/te
+mpdirectory/$filehash.png";

system $cmd;
[download]

And you will not get output. I still am not sure if this will output warning dialog though, if there was a issue.

Unfortunately it only works with the cp (copy) and not other commands like rm.

John