I have about 10 folders containing some pdfs that I need to merge based on the file name. The naming convention is like "acctnumber_12345.pdf" and each acctnumber has multiple pdfs associated with it. I want to merge everything for each account under a new name convention "acctnumber.pdf". Is there a script or any easy way to get it done? FYI, I'm using a Windows OS and I have thousands of files.