System Start Up and Shut Down

Linux startup is normally performed through LILO (Linux Linker and Loader). LILO 'bootstraps' the system and gets it going. The shutdown command should be used to shutdown the Linux system securely. Only root users may shutdown the system. Once the shutdown command is issued, all users are notified and new logins are not allowed. A time delay before shutdown and the operations that should be performed after shutdown may be specified using the shutdown command's options. The following are some common ways to issue the shutdown command:

• Shut down now and reboot:

    # shutdown -r now

• Shut down in 5 minutes; do not reboot (halt)

    # shutdown -h +5 

• Shut down at 5:00pm

    # shutdown -h 17:00 

It is a good idea to issue a 'sync' command to flush the information in buffers and caches and write the information to the disk before an immediate shutdown. This brings the system's state up-to-date.

    # sync