What type of log file is /var/log/wtmp used for?

The file located at /var/log/wtmp serves as a log of user login records on a Linux system. This log specifically tracks successful logins and logouts, as well as system reboots.

When a user logs in to the system, a record is added to the wtmp file, which maintains a historic account of user sessions. This information is crucial for monitoring user activity, auditing system access, and maintaining security protocols. System administrators can use tools like who, last, or lastb to read this log and check login history, which provides insights into user behavior and can help identify unauthorized access attempts.

Other log types mentioned, such as system error logs or application event logs, are stored in different files, usually within the /var/log directory as well, but they serve different purposes unrelated to tracking user logins.