what two commands can be used to reboot the linux system
The correct answer and explanation is:
The two commands commonly used to reboot a Linux system from the command line are reboot and shutdown.
Correct Answer:
- reboot
- shutdown (specifically with the -r option, e.g., shutdown -r now)
Explanation:
Linux systems provide multiple commands to perform system-level tasks like rebooting, each with slightly different nuances and typical use cases.
The first command, reboot, is arguably the most direct and straightforward way to restart a Linux system. When you execute the reboot command, the system prepares for a shutdown by sending signals to running processes, unmounting filesystems, and then initiating a system restart. On modern Linux distributions using systemd, the reboot command is often a symbolic link or alias to systemctl reboot. This command is typically used when you want to restart the system immediately without needing to specify timings or send messages to other users. Like most system-wide commands, running reboot requires elevated privileges, usually as the root user or by using the sudo command: sudo reboot.
The second command, shutdown, is a more versatile utility designed for scheduled or immediate system state changes, including shutting down, halting, or rebooting. To use shutdown specifically for rebooting, you need to include the -r option, which stands for ‘reboot’. The command also requires a time argument. For an immediate reboot, you use the keyword now. So, the command becomes shutdown -r now. A key difference is that shutdown, especially when used with a future time (e.g., shutdown -r +5 for a reboot in 5 minutes), sends warning messages to all logged-in users, allowing them time to save their work. Using now often bypasses these warnings on modern systems but retains the shutdown utility’s framework. Similar to reboot, executing shutdown -r now requires root privileges: sudo shutdown -r now.
While both commands achieve the same outcome of restarting the system, reboot is simpler for immediate restarts, whereas shutdown -r now is part of a more comprehensive utility that offers additional options for graceful shutdowns and scheduling.