Folks: As you've no doubt heard, there are now SHA1 collisions in the wild: http://shattered.io/
(See also, if you're interested, https://z.cash/blog/hash-functions.html .) The invocation docs for sha1sum should be updated to reflect this, and also — as with the md5sum invocation docs — b2sum should be suggested as an alternative. Also, these web pages should be updated to newer a coreutils release so that these recommendations are visible there: https://www.gnu.org/software/coreutils/manual/html_node/md5sum-invocation.html Regards, Zooko
