After editing .bashrc commands return 'command could not be located because '/bin' is not included in the PATH' [duplicate]
It looks like your PATH variable got messed up.
If this ever happens to you, and you are running a /bin/sh (or variant such as /bin/bash)....enter the following on the command line:
export PATH=/bin:/usr/bin:/usr/local/bin:/sbin:/usr/sbin
Then you will be able to easily use the base UNIX commands without having to prefix them with /....blah..../command while you are fixing the problem.