how do I replace.... text quesiton
 

how do I replace all occurences of

><

with

>
<

?


thank you

This looks like it might be homework---please tell us a bit more about the context.

Have you looked at SED? Here's the most often recommended tutorial:
http://www.grymoire.com/Unix/Sed.html (Look at the "s" command)

Since this is almost certainly homework, I will say that you need to insert a linefeed between the two characters, and you can do it with a very simple Bash script.

A cheat is to use rpl (not installed on a lot of linux distributions by default) but you still have to insert a linefeed between the characters.