Lock or UnLock Linux User Account
To lock the account
sudo passwd -l username |
To unlock the account (this command will change the password back to its previous value)
sudo passwd -u username |
All about Information Technology!
To lock the account
sudo passwd -l username |
To unlock the account (this command will change the password back to its previous value)
sudo passwd -u username |
The above command actually adds (or removes) a ‘!’ or ‘!!’ in front of the hashed password entry in /etc/shadow:
.
user:$1$0AR6z6sk$2bW8iFthim9u7be0:15537:0:99999:7:::
becomes:
user:!$1$0AR6z6sk$2bW8iFthim9u7be0:15537:0:99999:7:::
NOTEs:
1. Certain older versions of passwd (ie. RHEL/CentOS 5.5 and others) just used to remove ‘!’ from hash value to unlock user, without the -f (force) flag and no other check or notice. Running passwd -u for a second time made the hash value: ‘::’ in other words empty, resulting in a non-password user
2. Certain versions of sshd, even if you only use public key authentication, require shadow entry for given user NOT to begin with a ‘!’ (or to be ‘!!’). In that case the user is reported as ‘locked’.