Hmm, I don't know of a good reference on this particular issue, maybe someone else does, it is more of an operating system issue than a perl issue though. Windoze/DOS likes double quotes and *nix prefers single. I've had that particular issue bite me in the behind enough to recognize it when I see it. I would recommend though when faced with an odd problem such as this create a little test script that duplicates the problem and then just try different things. A lot of times the errors you get doing this along with simplifying it down to it's essence is enough to figure it out on your own. You get to learn something along the way as a bonus!