The pwdutils package should supply the mkpasswd program.
The results of "mkpasswd -S <salt_string> -m sha-512" is an 86 digit long string, after the type and salt.
echo -n 'ThisIsATest' | /usr/bin/mkpasswd -m sha-512 -S 'salt1234' -
Some distro's use the blowfish hash by default (see man 3 crypt) however, I don't believe that mkpasswd supports blowfish.
Last edited by jschiwal; 10-14-2010 at 08:26 PM.