cmp is a command line utility for computer systems that use Unix or a Unix-like operating system. It compares two files of any type and writes the results to the standard output. By default, cmp is silent if the files are the same; if they differ, the byte and line number at which the first difference occurred is reported.
cmp may be qualified by the use of command-line switches. The switches supported by the GNU version of cmp are:
Operands that are byte counts are normally decimal, but may be preceded by '0
' for octal and '0x
' for hexadecimal.
A byte count can be followed by a suffix to specify a multiple of that count; in this case an omitted integer is understood to be 1. A bare size letter, or one followed by 'iB
', specifies a multiple using powers of 1024. A size letter followed by 'B
' specifies powers of 1000 instead. For example, '-n 4M
' and '-n 4MiB
' are equivalent to '-n 4194304
', whereas '-n 4MB
' is equivalent to '-n 4000000
'. This notation is upward compatible with the SI prefixes for decimal multiples and with the IEC 60027-2 prefixes for binary multiples.