Which command is used to determine which users have logged into the system?

• A. who
• B. last
• C. lastlog
• D. w

Answer: (C)

To find out which accounts have accessed the system, you want a per-user login history. The lastlog tool reads the last login time for every account from the system’s lastlog record and prints a line for each user, showing the most recent login (or indicating that never logged in). This gives a complete view of which users have ever logged in. It differs from who, which shows only users currently logged in; from w, which also shows current activity; and from last, which presents recent login events in sequence rather than a full per-user last-login snapshot. So lastlog is the right choice for listing which users have logged into the system.