Linux Command #62 – loginctl (Linux OS)

2026-10-22

Linux Command #62 – loginctl (Linux OS)

Anime-realistic Linux technician reviewing journalctl logs in a server room

Linux Command #62 — loginctl introduces the systemd login manager’s command-line interface for inspecting local users, login sessions, and seats. This command is distinct from hostnamectl, which describes the host itself.

What loginctl Does

loginctl talks to systemd-logind, the service that tracks user sessions and seats on many Linux distributions. It helps administrators answer who is logged in, which session belongs to which user, and whether a session is active. This is useful for workstation and shared-server diagnostics.

loginctl list-sessions

The output generally includes session IDs, user IDs, usernames, seats, and TTYs when applicable. Remote SSH sessions may not have a physical seat. If the system is not using systemd-logind, these commands may not apply.

Inspect One Session

loginctl show-session SESSION_ID

Replace SESSION_ID with a value from list-sessions. Look for properties such as Name, Remote, State, and Type. Available properties depend on systemd version and configuration.

See User Sessions

loginctl list-users
loginctl user-status USERNAME

These commands identify users known to logind and show session or process details. Avoid publishing user identifiers or private login details in screenshots and logs.

View Seat Information

loginctl list-seats
loginctl seat-status seat0

A seat is a collection of hardware devices such as a keyboard, display, and input devices that can be assigned to a local session. Headless servers may have different seat behavior.

Active Sessions and Security

A session marked active is not proof that the human user is present, and a user without a listed logind session may still own background processes. Compare results with who, w, and service logs when investigating a problem. Do not terminate other people’s sessions without approval.

Administrative Operations

sudo loginctl terminate-session SESSION_ID

Warning: This is a disruptive example, not a diagnostic step. It can end a user’s work and terminate associated processes. Use only with explicit authorization, an identified session, and a recovery plan.

Practical Lab

1. Run loginctl list-sessions. 2. Identify your own session ID. 3. Run loginctl show-session SESSION_ID. 4. Record whether the session is local or remote. 5. Run loginctl list-users. Do not alter any sessions during this exercise.

Troubleshooting

If loginctl cannot contact the service, inspect whether the machine uses systemd-logind, whether D-Bus and the relevant service are functioning, and whether permissions allow the request. Containers and minimal environments may not run a full logind service.

Knowledge Check

1. What service does loginctl communicate with? 2. What is the difference between a session and a seat? 3. Which command shows properties of one session? 4. Why should terminate-session require authorization?

Answers: (1) systemd-logind. (2) A session is a user’s login context; a seat is an assigned group of local hardware. (3) loginctl show-session SESSION_ID. (4) It can interrupt a user’s work and end processes.