So, today I was using the c shell on a freshly installed BSD system (hadn't gotten around to setting up bash yet). While trying to cat out a file, I accidentally cat a directory instead. As a result, some sequence of the binary output changed my shell echos. Of source, I simply typed in "reset" to be able to echo normal text again, but now my backspace key was no longer working. Instead of erasing the previous character, I was getting something more like this:

$ cd /uss^?^?^?

The answer. luckily, is pretty simple. Reset the terminal's erase character to backspace. Just type the following:

$ stty erase ^?

Do NOT actually type in "^?". When you hit the backspace key, it should make those characters for you. If performed successfully, you will have a working backspace key again.

I hope this helps!