Note_Tech

All technological notes.

Project maintained by simonangel-fong Hosted on GitHub Pages — Theme by mattgraham

Linux - System: Shutdown

Linux - System: Shutdown

Power Off/Shutdown the system

Shutdown/Power Off
- All running processes are terminated.
- Filesystems are unmounted, and disks are safely synced.
- The machine powers down.
shutdown delay
- give users time to save their work and log off the system.
Commands

CMD	DESC
`poweroff`	Turns off the system
`shutdown now`	Turns off the system immeidately
`shutdown +5`	Shutdown in 5 minutes
`systemctl poweroff`	Turns off the system

poweroff is the symbolic link to systectl equivalents

Reboot the system

Restarts the system by powering it off and back on.
Filesystems are synced and unmounted.
Reinitializes the entire boot process.
Important:
- restarting is considered downtime on a server and should be avoided if possible.
- Try to use systemctl restart {service-name} to restart services rather than reboot the whole system.
Commands

CMD	DESC
`reboot`	Reboots the system immediately
`shutdown -r now`	Reboots the system immediately
`shutdown -r 22:00`	Reboots the system at 10pm
`systemctl reboot`	Reboots the system immediately

reboot is the symbolic link to systectl equivalents

Halt

Halt
- Stops the operating system without cutting power to the machine.
- Halts all CPU activity.
- Filesystems are synced and unmounted.
- The system remains powered on (useful for maintenance tasks).

CMD	DESC
`halt`	Halt the system
`shutdown --halt 22:00`	Halt the system at 10pm
`shutdown --halt +5`	Halt the system after a five-minute delay
`shutdown --halt +5 "message"`	Halt the system after a delay and append a message to all users
`shutdown -c`	Cancel a timed shutdown
`systemctl halt`	Halt the system

Suspend (Sleep) and Hibernate

Suspend (Sleep)
- Puts the system into a low-power state while keeping the session in memory (RAM).
- Current state is saved in RAM (volatile memory).
- Power to most hardware components (like the CPU) is reduced or turned off.
- Quick to resume as RAM remains powered.
- Use Case:
  - Temporary breaks; resumes quickly without full system restart.

Hibernate(冬眠) the system:
- Saves the system state to the disk and powers off completely.
- System state is saved to a swap partition or file.
- Power is completely cut off.
- On reboot, the system restores the session from disk.
- Use Case:
  - Longer breaks; resumes from where you left off but takes longer than suspend.

Commands

CMD	DESC
`systemctl suspend`	Suspend the system
`systemctl hibernate`	Hibernate the system
`systemctl hybrid-sleep`	Both suspends and hibernates the system