man : cmp(1)
CMP(1) OpenBSD Reference Manual CMP(1)
cmp - compare two files
cmp [-l | -s] file1 file2 [skip1 [skip2]]
The cmp utility 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.
Bytes and lines are numbered beginning with one.
The options are as follows:
-l Print the byte number (decimal) and the differing byte values
(octal) for each difference.
-s Print nothing for differing files; return exit status only.
The optional arguments skip1 and skip2 are the byte offsets from the
beginning of file1 and file2, respectively, where the comparison will
begin. The offset is decimal by default, but may be expressed as a
hexadecimal or octal value by preceding it with a leading ``0x'' or
The cmp utility exits with one of the following values:
0 The files are identical.
1 The files are different; this includes the case where one
file is identical to the first part of the other. In the
latter case, if the -s option has not been specified, cmp
writes to standard error that EOF was reached in the
shorter file (before any differences were found).
>1 An error occurred.
diff(1), diff3(1), sdiff(1)
The cmp utility is compliant with the IEEE Std 1003.1-2008 (``POSIX'')
The arguments skip1 and skip2 are extensions to that specification.
A cmp command appeared in Version 1 AT&T UNIX.
OpenBSD 4.9 September 3, 2010 OpenBSD 4.9