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CMP(1) NetBSD General Commands Manual CMP(1)
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cmp -- compare two files
cmp [-c] [-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 differ-
ence occurred is reported.
Bytes and lines are numbered beginning with one.
The following options are available:
-c Do the compare using getc(3) rather than mmap(2). Combined with
the -l flag, this can be helpful in locating an I/O error in the
-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 an
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 output
that EOF was reached in the shorter file (before any differences
>1 An error occurred.
comm(1), diff(1), diff3(1), sdiff(1)
The cmp utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compati-
The cmp utility first appeared in Version 1 AT&T UNIX.
NetBSD 9.2 December 13, 2016 NetBSD 9.2