Linux Shutdown Command

The shutdown command safely powers off or restarts the system. It warns all logged-in users and blocks new logins during the final 5 minutes.

Basic Syntax : shutdown [OPTIONS] TIME [MESSAGE]

TIME formats

• now → shutdown immediately
• hh:mm → shutdown at a specific time
• +minutes → shutdown after a delay

Requirement : The shutdown command needs administrative/root access.

Example :

shutdown now                    # Shutdown right now
shutdown 01:51                  # Shutdown at 01:51
shutdown +1 "Goodbye World!"    # Shutdown after 1 minute with a custom message 
date                            # Check system time (often UTC)