You can type any Linux command by entering the full path, just apply btmiller's advice. If you know where cp and mv have been moved to, you can enter the full path.
/some/bad/place/mv source destination
/some/bad/place/cp -a source destination
try using a Linux "LiveCD." This is a CD-ROM that runs a Linux distribution without installing to the hard drive. Some people use them to "try out" Linux without messing up the hard drive, but they're very useful as rescue discs. Just put the disc in the CD-ROM drive and boot your computer. The LiveCD loads instead of your regular operating system.
Getting a LiveCD:
Do you have the CD-ROMs from the distribution you installed? Many distros can use the first installation disk as a LiveCD. For example, boot from Red Hat disc 1 and type "linux rescue" at the boot: prompt.
You can also download and burn a more complete LiveCD. One of the most popular is Knoppix
. It loads a complete X Window system. You could also try Damn Small Linux
You can also download powerful rescue floppy such as Tom Oehser's tomsrtbt
Any good LiveCD will allow you to mount your regular disk partition so you can make changes to it. (Knoppix does this automatically).
You can then
cp -a /mnt/mylinuxpartition/some/bad/place/bin /mnt/mylinuxpartition/bin
You'd be using the LiveCD's copy of cp, mv, etc.