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CMP(1) DragonFly General Commands Manual CMP(1)
cmp - compare two files
cmp [-l, --verbose | -s, --silent, --quiet | -x] [-hz] file1 file2
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 following options are available:
-h Do not follow symbolic links.
Print the byte number (decimal) and the differing byte values
(octal) for each difference.
-s, --silent, --quiet
Print nothing for differing files; return exit status only.
-x Like -l but prints in hexadecimal and using zero as index for the
first byte in the files.
-z For regular files compare file sizes first, and fail the
comparison if they are not equal.
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
>1 An error occurred.
Assuming a file named example.txt with the following contents:
Compare stdin with example.txt:
$ echo -e "a\nb\nc" | cmp - example.txt
Same as above but introducing a change in the third byte of stdin. Show
the byte number (decimal) and differing byte (octal):
$ echo -e "a\nR\nc" | cmp -l - example.txt
3 122 142
Compare file sizes of example.txt and /boot/loader.conf and return 1 if
they are not equal. Note that -z can only be used with regular files:
$ cmp -z example.txt /boot/loader.conf
example.txt /boot/loader.conf differ: size
Compare stdin with example.txt omitting the first 4 bytes from stdin and
the first 2 bytes from example.txt:
$ echo -e "a\nR\nb\nc" | cmp - example.txt 4 2
The cmp utility is expected to be IEEE Std 1003.2 ("POSIX.2") compatible.
The -h, -x, and -z options are extensions to the standard.
A cmp command appeared in Version 1 AT&T UNIX.
DragonFly 5.9-DEVELOPMENT January 15, 2021 DragonFly 5.9-DEVELOPMENT