패스워드에 lock 걸어 잠그기
[root@push06 skel]# passwd -l kbs
Locking password for user kbs.
passwd: Success
[root@push06 skel]# grep kbs /etc/shadow
kbs:!!$1$aPkNiTws$ZV5bM4sc48RINJ0vK5U3f0:15947:0:99999:7:::
[root@push06 skel]# passwd -u kbs
Unlocking password for user kbs.
passwd: Success.