Regular expression for filename replacement with the value of the parameter replacement.

If the expression matches the filename then the groups found are replaced.

a) For replacement "capturing groups" are used. Only the content of the capturing groups is replaced.

Replacements are separated by a semicolon ";". Example:

replacing = (1)abc(12)def(.*)
replacement = A;BB;CCC
Name of original file: 1abc12def123.txt
Name after renaming: AabcBBdefCCC

b) If no "capturing groups" are specified then the entire match is replaced. Example:
replacing = Hello
replacement = 1234
Input file: Hello_World.txt
Output file: 1234_World.txt

Requires the parameter replacement to be specified.