Server Issues

I'm trying to set up a server, and its set up on a mac. It won't let me enable command blocks, even though I've tried to go into server.properties and I change it, then I go back into my server and it says "command blocks are not enabled" . Anyone have a Skype I can show my screen to? (I need someone who is GREAT at setting up servers or someone who is great at using macs please)
Thanks,
CatDomination