File names are of random length, and the number of digits in the _<numbers here> string is arbitrary, but right now, between 1 and 7 digits.
All files are currently in the form: <Number I want to keep>_<Usless ID Ref>(Real ID I need to keep).ext
eg: 123-ABC_98765(Type-A).pdf. I need it to be 123-ABC (Type A).pdf. I have thousands of files to perform this rename on.
I am not strong at regular expressions at all; I don't even know if they might be used here. Any direction would be greatly appreciated.