I use EditPlus.
This tool has a nice search option where you can search either regular text or RegEx search.
I want to search for the next Uppercase alphabet preceeded by a lowercase alphabet. What do I put in the search box for this?
[A-Z][a-z]+
should do it.
Translation: Exactly one capital letter, followed by one or more lowercase letters.
Edit: I had the relationship backwards:
[a-z]+[A-Z]+
Translation: One or more lower-case letters, followed by one or more upper-case letters.