File Permissions and content cached

Hi, I’ve got some trouble updating the php files in my themes folder.

I’ve tried editing directly using command line vi over ssh, and saved the file, though when I view the page, nothing has changed. I’ve also tried to use the built in theme editor as an alternative, which displays to me the old version of the file, and claims it’s not writable (even though I’ve checked the file ownership and permissions 777 just for testing). I’m assuming that the theme editor displaying and old version and the actual web page not updating are related, but I’ve been unsuccessful in my attempts to figure out what is causing it.