What is the command to unlock a user’s account in Linux?

In Linux, to unlock a user account, the command used is not accurately represented by the choice provided. The correct approach to unlocking a user's account typically involves using the passwd command with the -u option, which is specifically intended to unlock a user account that has previously been locked. The usermod command options listed do not correspond to the action of unlocking an account.

The usermod command is predominantly used for modifying user account attributes such as group memberships, user IDs, or login names rather than directly unlocking accounts. Therefore, while unlocking an account is a common administrative task, it is not achieved using usermod -u, -aG, -l, or -g options.

For unlocking an account, the correct command would typically look like this:

passwd -u username

This command unlocks the account associated with 'username,' ensuring that the user can log in again. Understanding the specific commands tied to user account management is vital for effective Linux administration.