This rule finds text that matches the specified RegEx pattern, and replaces it with another string. (RegEx is short for Regular Expressions).
The RegEx syntax is explained here.
The ReNamer users have contributed many RegEx patterns for various purposes. You can copy and use them.
The parameters are as follows:
|Expression||RegEx pattern to match (find).|
|Replace||RegEx pattern that replaces the found pattern.|
|Skip extension||If this check box is unselected, the extension will be included in the rule.|