Moving Website Files Up One Folder

I am trying to figure out the best way to move some files around and I've run across errors when I have tried already and am looking for something that would work.

So here is my situation:

I have an active website located in /home/USERNAME/public_html/ (Normal Stuff)

I also have a Development Site that is complete and ready to go. It is located at: /home/USERNAME/public_html/DEVEL/

Now we want the contents of the of the DEVEL folder to be up one folder level to the public_html level. We know we will have to change the config file of the app I am using but that aside I am looking for the best method for moving files like this.

One other thing to note is that I have one folder that must stay in the public_html folder so I can just blindly delete everything in the public-html folder prior to moving what is in /public_html/DEVEL/ up one level.

Your assistance is greatly appreciated.

Thanks!

LVWH