CKSUM

Section: User Commands (1)
Updated: February 2026
Index Return to Main Contents

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NAME

cksum - compute and verify file checksums  

SYNOPSIS

cksum [,OPTION/]... [,FILE/]...  

DESCRIPTION

Print or verify checksums. By default use the 32 bit CRC algorithm.

With no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-a'-a, --algorithm=,TYPEX'tty: link'/

select the digest type to use. See DIGEST below

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-base64'--base64X'tty: link'

emit base64-encoded digests, not hexadecimal

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-c'-c, --checkX'tty: link'

read checksums from the FILEs and check them

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-l'-l, --length=,BITSX'tty: link'/

digest length in bits; must not exceed the max size and must be a multiple of 8 for blake2b; must be 224, 256, 384, or 512 for sha2 or sha3

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-raw'--rawX'tty: link'

emit a raw binary digest, not hexadecimal

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-tag'--tagX'tty: link'

create a BSD-style checksum (the default)

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-untagged'--untaggedX'tty: link'

create a reversed style checksum, without digest type

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-z'-z, --zeroX'tty: link'

end each output line with NUL, not newline, and disable file name escaping

 

The following five options are useful only when verifying checksums:

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-ignor-missing'--ignore-missingX'tty: link'

don't fail or report status for missing files

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-quiet'--quietX'tty: link'

don't print OK for each successfully verified file

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-status'--statusX'tty: link'

don't output anything, status code shows success

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-strict'--strictX'tty: link'

exit non-zero for improperly formatted checksum lines

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-w'-w, --warnX'tty: link'

warn about improperly formatted checksum lines

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-debug'--debugX'tty: link'

indicate which implementation used

X'tty: link https://www.gnu.org/software/coreutils/cksum#cksu-help'--helpX'tty: link'

display this help and exit

X'tty: link https://www.gnu.org/software/coreutils/cksum#cksu-version'--versionX'tty: link'

output version information and exit

 

DIGEST determines the digest algorithm and default output format:

sysv

(equivalent to sum -s)

bsd

(equivalent to sum -r)

crc

(equivalent to cksum)

crc32b

(only available through cksum)

md5

(equivalent to md5sum)

sha1

(equivalent to sha1sum)

sha2

(equivalent to sha{224,256,384,512}sum)

sha3

(only available through cksum)

blake2b

(equivalent to b2sum)

sm3

(only available through cksum)

When checking, the input should be a former output of this program, or equivalent standalone program.  

AUTHOR

Written by Padraig Brady and Q. Frank Xia.  

REPORTING BUGS

Report bugs to: bug-coreutils@gnu.org

Report Gentoo bugs to: https://bugs.gentoo.org/
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Report any translation bugs to <https://translationproject.org/team/>  

SEE ALSO

Full documentation <https://www.gnu.org/software/coreutils/cksum>
or available locally via: info aq(coreutils) cksum invocationaq

Packaged by Gentoo (9.10 (p0))
Copyright © 2026 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

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Index

NAME

SYNOPSIS

DESCRIPTION

The following five options are useful only when verifying checksums:

DIGEST determines the digest algorithm and default output format:

AUTHOR

REPORTING BUGS

SEE ALSO