md5, sha1,
sha256, sha512 —
calculate a message digest (checksum) for a file
md5 |
[-bcpqrtx] [-C
checklist] [-h
hashfile] [-s
string] [file ...] |
sha1 |
[-bcpqrtx] [-C
checklist] [-h
hashfile] [-s
string] [file ...] |
sha256 |
[-bcpqrtx] [-C
checklist] [-h
hashfile] [-s
string] [file ...] |
sha512 |
[-bcpqrtx] [-C
checklist] [-h
hashfile] [-s
string] [file ...] |
These utilities take as input a message of arbitrary length and produce as
output a message digest (checksum) of the input.
Two messages having the same message digest (a collision) have
been produced for MD5 and for SHA-1, so their use is deprecated.
The options for use with each command are as follows:
-b- Output checksums in base64 notation, not hexadecimal.
-C
checklist- Compare the checksum of each file against the
checksums in the checklist. Any specified
file that is not listed in the
checklist will generate an error.
-c- If this option is specified, the file options become
checklists. Each checklist should contain hash results in the normal
format, which will be verified against the specified paths. Output
consists of the digest used, the file name, and an OK, FAILED, or MISSING
for the result of the comparison. This will validate any of the supported
checksums (see cksum(1)). If no file is
given, stdin is used.
-h
hashfile- Place the checksum into hashfile instead of
stdout.
-p- Echoes stdin to stdout and appends the checksum to stdout.
-q- Only print the checksum (quiet mode) or if used in conjunction with the
-c flag, only print the failed cases.
-r- Reverse the format of the hash algorithm output, making it match the
output format used by cksum(1).
-s
string- Prints a checksum of the given string.
-t- Runs a built-in time trial. Specifying
-t multiple
times results in the number of rounds being multiplied by 10 for each
additional flag.
-x- Runs a built-in test script.
These utilities exit 0 on success, and >0 if an error occurs.
R. Rivest, The MD5
Message-Digest Algorithm, RFC 1321,
April 1992.
J. Burrows, The
Secure Hash Standard, FIPS PUB 180-1.
D. Eastlake and
P. Jones, US Secure Hash
Algorithm 1 (SHA1), RFC 3174,
September 2001.
Secure Hash Standard,
FIPS PUB 180-2.