In computing, comp is a command used on DEC OS/8,[1] DOS,[2] DR FlexOS,[3] IBM OS/2,[4] Microsoft Windows[5] and related computer operating systems such as ReactOS.

It is used to perform comparisons of multiple computer files to show the differences between them.

A newer command, fc was added in DOS 3.3 which allows for line comparisons in addition to binary comparisons.

DR DOS 6.0 also includes an implementation of the comp command.

[9] Ged Murphy developed the ReactOS version.