diffpdfc is used to compare two PDF files—textually or visually.

C:\> diffpdfc.exe

diffpdfc is a windows console (command line) program for comparing two PDF files.
(If you require an interactive graphical user interface (GUI) tool, use our DiffPDF application instead.)

Application: diffpdfc
The trial license key will be specific to this machine. (Download and install diffpdfc if you haven't already done so. Then run diffpdfc with the --register command line option to show the Register window. This window shows the Computer ID. If it doesn't match the one shown here (or if this one is empty),. Click the “Copy” icon beside the Computer ID to copy it to the clipboard, then paste it here.)

Note that only one trial per application per major version per machine is allowed.
Trial license keys are valid for 20 days.