compare two files
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
Bytes and lines are numbered beginning with one.
The options are as follows:
- Print the byte number (decimal) and the differing byte values (octal) for each difference.
- Silent. 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 “0”.
cmp utility exits with one of the
- The files are identical.
- 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
-soption has not been specified,
cmpwrites to standard error that
EOFwas reached in the shorter file (before any differences were found).
- An error occurred.
diff(1), diff3(1), sdiff(1)
cmp utility is compliant with the
IEEE Std 1003.1-2008 (“POSIX.1”)
The arguments skip1 and skip2 are extensions to that specification.
cmp command appeared in
Version 1 AT&T UNIX.