Similar to Diff

Dd (Unix)

Df (Unix)

Dirname

Du (Unix)

Echo (command)

Ed (text editor)

Env

Eval

Exit (command)

File (command)

Find (Unix)

Grep

Kill (command)

Ln (Unix)

Ls

Mesg

Mkdir

More (command)

Nl (Unix)

Pax (command)

Rm (Unix)

Rmdir

Split (Unix)

Tee (command)

Touch (command)

true and false (commands)