What command is utilized to unlock user accounts in Linux?

The command used to unlock user accounts in Linux is pam_tally. This utility is part of the Pluggable Authentication Module (PAM) system, which provides a way to manage user authentication. Specifically, pam_tally allows administrators to track login attempts and can be used to unlock user accounts that have been locked after exceeding the maximum number of failed login attempts.

When a user account gets locked, it is often due to security measures in place to prevent unauthorized access, and pam_tally helps manage this by offering options to reset the login attempts and, consequently, unlock the account.

The other options do not serve this purpose. The pwd command is used to print the working directory of the current user, cd is used to change directories, and top is a system monitoring tool that shows running processes and system resource usage. None of these commands relate to user account management or the specific function of unlocking accounts. Understanding how pam_tally works and its role in account management is essential for maintaining security and access control within a Linux environment.