It is a replacement for the service and chkconfig command in CentOS 7. The systemctl command is used to manage the different types of systemd objects (units). Systemd has 12 unit types, which can be listed with the command shown in the following screenshot:
The following table lists some popular units and their descriptions:
|
Unit types |
Description |
|
Service |
These types of units have a .service extension and represent the system services. This unit is used to start daemons such as the web server. If no unit name is specified with systemctl, then the service is assumed as the default unit. |
|
Socket |
These types of units have a .socket extension and represent inter-process communication (IPC) sockets. |
|
Path |
These type of units have a .path extension and are used to delay the activation of a service until a specific filesystem change occurs. |
|
Target |
These types of units have a .target extension and represent a group of units. |
|
Slice |
These types of units have a .slice extension and they represent a management unit of processes. |