Sometimes it might be usefull to replace text via regular expressions. This can be done with Notepad++
For example you with to replace all <a href="http://..." links in a textfile with <a href="/index.html" then open Notepad++ (V6.1.*) and enter in the searchfield (without the ' characters):
and in the replace field (without the ' characters):
'<a href="/index.html" '