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
“0”.
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).