or download this
$ perl -E 'use Digest::SHA "sha256_hex"; say sha256_hex("foobar")'
c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2
$ perl -E 'use Digest::SHA "sha256_hex"; say sha256_hex("foobar\n")'
aec070645fe53ee3b3763059376134f058cc337247c978add178b6ccdfb0019f