tr – Translate of Delete. This is the first time i am using this command and it was pretty nice. Used the gui repalce functionality on text editors so far and, sed recently. But this seems pretty nice.
tr 'abc' 'xyz' will replace the occurence of abc with xyz. Takes input from the standard input. Meaning if you run this command and type something in and press enter. You will see the results down below. Common use is to cat and pipeline the content though.