Is it possible to get a file extension without knowing it?

Question

I have a file called 94bf663a100e848fb599209af8cdc2b5.wmv. I know pathinfo will not give me the extension if I just use the name 94bf663a100e848fb599209af8cdc2b5. I

Answer 1

The first few characters of the file (binary) will usually give you some kind of hint about what the file type is.

Try it out by opening some binary files (rar, zip, mp3 etc.) in Notepad.