On GNU/Linux-based systems, a service is a type of daemon that is managing by an init script. Traditionally this would be a System V-style init script, located in the directory
/etc/init.d, but on modern systems it could be managed by upstart, systemd, or one of the other replacements for the System V init system that have been developed.
The preferred method for starting and stopping services on modern systems is by means of the
service command. Where available, this command allows a service to be controlled without needing to know how it is managed.