Substitute driven refactoring
If you ever find yourself renaming a core class of the application you should think about speed up the process. In case when class name or method name is unique - Substitute is dominating IDE refactoring tools. Running sever find/sed commands in console will cover everything except files renaming of course. Be very attentive and figure out all possible variants of name (CamelCase, under_score, plural/singular form). In order to not touch plural form while working with singular form start from plural form first.