Understanding Linux Services

In a Linux-based operating system, a service is a program that can be executed at startup and run in the background. The user can also execute it at any time from the command line. On a Linux dedicated server, services are very important, as most of the critical applications are run in this manner.

In most Linux distributions, services are found in /etc/init.d. To find out what commands can be executed for a given service, such as rsync, simply login as root and enter the following:

/etc/init.d/rsync

It will respond telling you how you can use it:

Usage: /etc/init.d/rsync {start|stop|reload|force-reload|restart|status}

Therefore, to start rsync, you would enter:

/etc/init.d/rsync

In Redhat Enterprise Linux, CentOS, and Fedora, you can run the following:

su - [then enter the root password] service rysnc start

You can apply the same formula to any service, such as apache (httpd) or sendmail, but be sure you know which services you are enabling or disabling before you try them.

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