I cannot type my password as shown below. After successfully unlocking root account in Ubuntu 12.04 LTS. saintmichael@ubuntu:~$ sudo usage: sudo [-D level] -h | -K | -k | -V usage: sudo -v [-AknS] [-D level] [-g groupname|#gid] [-p prompt] [-u user name|#uid] usage: sudo -l[l] [-AknS] [-D level] [-g groupname|#gid] [-p prompt] [-U user name] [-u user name|#uid] [-g groupname|#gid] [command] usage: sudo [-AbEHknPS] [-C fd] [-D level] [-g groupname|#gid] [-p prompt] [-u user name|#uid] [-g groupname|#gid] [VAR=value] [-i|-s] [<command>] usage: sudo -e [-AknS] [-C fd] [-D level] [-g groupname|#gid] [-p prompt] [-u user name|#uid] file ... saintmichael@ubuntu:~$ sudo ./sophos-av/install.sh [sudo] password for saintmichael: