File Buddy help | Renaming | Pattern-based renaming
Renaming method
The pop-up menu at the upper left of the Rename window specifies the basic rule to be used during the renaming process:
Replace String
Replace the given string with another string.
Delete String
Delete a specified string when it occurs in names.

Replace Characters
Replace the each of the characters in the first string with the corresponding character in the second string.
Delete Characters
Delete the given characters.

Replace Regexp
Replace regular expression patterns using standard Perl 5 syntax.

Use Original Name
Start with the item’s original name as a basis and use other options to generate the new name.
Replacement and deletion options Regular Expressions