cmp [OPTION]... FILE1 [FILE2 [SKIP1 [SKIP2]]]


Compare two files byte by byte.

The optional SKIP1 and SKIP2 specify the number of bytes to skip at the beginning of each file (zero by default).

Mandatory arguments to long options are mandatory for short options too.

-b, --print-bytes

print differing bytes

-i, --ignore-initial=SKIP

skip first SKIP bytes of both inputs

-i, --ignore-initial=SKIP1:SKIP2

skip first SKIP1 bytes of FILE1 and first SKIP2 bytes of FILE2

-l, --verbose

output byte numbers and differing byte values

-n, --bytes=LIMIT

compare at most LIMIT bytes

-s, --quiet, --silent

suppress all normal output


display this help and exit

-v, --version

output version information and exit

SKIP values may be followed by the following multiplicative suffixes: kB 1000, K 1024, MB 1,000,000, M 1,048,576, GB 1,000,000,000, G 1,073,741,824, and so on for T, P, E, Z, Y.

If a FILE is `-' or missing, read standard input. Exit status is 0 if inputs are the same, 1 if different, 2 if trouble.


Written by Torbjorn Granlund and David MacKenzie.


Report bugs to: [email protected]

GNU diffutils home page: <>

General help using GNU software: <>


Copyright © 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <>.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


diff(1), diff3(1), sdiff(1)

The full documentation for cmp is maintained as a Texinfo manual. If the info and cmp programs are properly installed at your site, the command

  • info cmp

should give you access to the complete manual.