How to lock a user account?

To lock a user account in Linux, you can use the passwd command with the -l option. This prevents the user from logging in by disabling their password. Here’s how to do it:

Open a terminal.
Run the following command, replacing username with the actual username of the account you want to lock:
```
sudo passwd -l username
```

This command will lock the user account by adding a ! in front of the password hash in the /etc/shadow file.

To verify that the account is locked, you can check the password status with:

sudo passwd -S username

If the account is locked, the output will indicate that the password is "locked."

To unlock the account later, you can use:

sudo passwd -u username

This will remove the lock and allow the user to log in again.