[NAME]
sha1sum \- compute and check SHA1 message digest
[DESCRIPTION]
.\" Add any additional description here
[BUGS]
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)