Provided by:
coreutils_8.26-3ubuntu3_amd64 
NAME
sha1sum - compute and check SHA1 message digest
SYNOPSIS
sha1sum [OPTION]... [FILE]...
DESCRIPTION
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)
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.
AUTHOR
Written by Ulrich Drepper, Scott Miller, and David Madore.
REPORTING BUGS
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Report sha1sum translation bugs to
<http://translationproject.org/team/>
COPYRIGHT
Copyright © 2016 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later <http://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.
SEE ALSO
Full documentation at: <http://www.gnu.org/software/coreutils/sha1sum>
or available locally via: info '(coreutils) sha1sum invocation'