How to Change Settings to Open a PDF File. A Portable Document File is a type of file that uses an open standard across different computer platforms and programs.

Press "Alt-F2" to open a command line prompt within Unity. Type the command for Evince with your PDF file's name, file extension and its full path relative to the Home directory.

Though DAT files, which house data as the shortened name implies, are usually best left alone, here's how you can open them.