sha1sum

Calculate the SHA1 checksum for a file

$ sha1sum [filename1]

Calculate SHA1 checksums for multiple files

$ sha1sum [filename1] [filename2]

Calculate and save the list of SHA1 checksums to a file

$ sha1sum [filename1] [filename2] > [filename.sha1]

Read a file of SHA1 sums and verify all files have matching checksums

$ sha1sum --check [filename.sha1]

Only show a message for files for which verification fails

$ sha1sum --check --quiet [filename.sha1]

sha1sum [OPTION]... [FILE]...

Print or check SHA1 (160-bit) checksums.

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

-b, --binary

read in binary mode

-c, --check

read SHA1 sums from the FILEs and check them

--tag

create a BSD-style checksum

-t, --text

read in text mode (default)

-z, --zero

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

The following five options are useful only when verifying checksums:

--ignore-missing

don't fail or report status for missing files

--quiet

don't print OK for each successfully verified file

--status

don't output anything, status code shows success

--strict

exit non-zero for improperly formatted checksum lines

-w, --warn

warn about improperly formatted checksum lines

--help

display this help and exit

--version

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.

Note: There is no difference between binary mode and text mode on GNU systems.

Do not use the SHA-1 algorithm for security related purposes. Instead, use an SHA-2 algorithm, implemented in the programs sha224sum(1), sha256sum(1), sha384sum(1), sha512sum(1), or the BLAKE2 algorithm, implemented in b2sum(1)

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
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Copyright © 2020 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.

Full documentation <https://www.gnu.org/software/coreutils/sha1sum> or available locally via: info '(coreutils) sha1sum invocation'

Written by Ulrich Drepper, Scott Miller, and David Madore.