I have several instances of a variable or a phrase, and I want to rename it. How do I edit all of them at the same time in Notepad++?
CTRL+H to get to the Replace dialog (or Search ==> Replace via the menu).
Input the string to find and input the string to replace it with and then hit the 'replace all' button on the right.
You can also use Notepad++'s Mutli-Editing feature to do this inline.