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CKSUM

Section: User Commands (1)
Updated: February 2026
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cksum - compute and verify file checksums

cksum [,OPTION/]... [,FILE/]...

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

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

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

Written by Padraig Brady and Q. Frank Xia.