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SHA1SUM
Section: User Commands (1)Updated: February 2026
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NAME
sha1sum - compute and check SHA1 message digestSYNOPSIS
sha1sum [,OPTION/]... [,FILE/]...DESCRIPTION
Print or check SHA1 (160-bit) checksums. Legacy interface to the cksum utility.
With no FILE, or when FILE is -, read standard input.
- X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-b'-b, --binaryX'tty: link'
- read in binary mode
- 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-tag'--tagX'tty: link'
- create a BSD-style checksum
- X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-t'-t, --textX'tty: link'
- read in text mode (default)
- 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/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
The sums are computed as described in FIPS-180-1. When checking, the input should be a former output of this program. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*' for binary, ' ' for text or where binary is insignificant), and name for each FILE.
There is no difference between binary mode and text mode on GNU systems.
BUGS
Do not use the MD5 algorithm for security related purposes. Instead, use an SHA-2, SHA-3, or BLAKE2 algorithm, implemented in the cksum(1) program.AUTHOR
Written by Ulrich Drepper, Scott Miller, and David Madore.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
cksum(1)
Full documentation <https://www.gnu.org/software/coreutils/sha1sum>
or available locally via: info aq(coreutils) sha1sum 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.