I have always been a fan of Eclipse IDE's and I thought I would point out that they also have a PHP IDE which I found just a little heads up if you didn't know already. However this thread is not about that. Today I deleted the wrong file in a project, meaning I lost quite a bit of code, I searched around and found that you can actually retrieve files back (thankfully the developers knew how clumsy people get using a keyboard & mouse). Anyway it's quite simple to do so, I will explain it as I found it to be quite a neat little feature and will help people who do this by mistake.
Click your project name.
Then right click and scroll down and find "Restore from Local History".
All the files you may have deleted I'm not sure how long ago or if it wipes each time you close Eclipse but they should be there.
Tick the boxes of files you want back, then click restore. You should have them all back! :D