Learning Debian GNU/Linux

Starting and Stopping the System and Services

Using Linux commands, you can start and stop the system or start and start services, such as the Apache web server.

Starting and Stopping the System

Generally, you start your system by turning on its power. However, you can use a Linux command to cause a system to restart itself. If you enter the command:

shutdown -r now

the system will immediately begin to shut down. Once it’s shut down, it will reboot. If you want to provide a delay before commencing the shutdown, use this form of the command:

shutdown -r +mm

where mm gives the number of minutes until the shutdown commences. The command displays a message to system users who have active shells displaying a command prompt. After commencement of a shutdown, users cannot initiate new login sessions.

If you want to halt the system, that is, shut down the system without causing it to reboot, use the command:

shutdown -h now

Starting and Stopping Services

Services are daemon programs that run without an associated console. They listen for network connections from clients, which request them to perform an action or provide information. Table 7-1 describes some of the most important services.

Table 7-1. Important Services

Service	Function
apache	Web server
atd	Runs commands at predefined times.
cron	Runs commands at predefine times; offers more flexibility than atd.
exim	Mail transfer agent.
gpm	Provides cut and paste to virtual consoles.
lpd	Controls the printer. ...