In computing, comp is a command used on DOS, Microsoft Windows and related computer operating systems, which performs a binary comparison of multiple files and shows the differences between them. The comp command first appeared in PC DOS 1.0 and has been included in most versions of MS-DOS and PC DOS. It is also included as a console command in Windows. A newer command, fc was added in DOS 3.3 which allows for line comparisons in addition to binary comparisons.