22.30.1. cksum, sum -- display file checksums and block counts
neo@MacBook-Pro ~ % head -20 /dev/urandom | cksum | cut -f1 -d " "
1705222024
22.30.2. md5sum - compute and check MD5 message digest
[root@localhost ~]# md5sum /etc/hosts
54fb6627dbaa37721048e4549db3224d /etc/hosts
[root@localhost ~]# sha1sum /etc/hosts
7335999eb54c15c67566186bdfc46f64e0d5a1aa /etc/hosts
