Usage of Systemctl in RHEL 7

1. # SYSTEMCT

   Systemctl can list the status of a running service

2. # Systemd-cgls

SYSTEMD-CGLS lists the running processes in a tree, which can recursively display control group content

3. How do I start/turn off, enable/disable services?

Start a service:systemctl start postfix.service
To close a service:systemctl stop postfix.service
To restart a service:systemctl restart postfix.service
Displays the status of a service:systemctl status postfix.service
enable a service at boot time:systemctl enable postfix.service
Disable a service at boot time:systemctl disable postfix.service
To see if the service is booting up:systemctl is-enabled postfix.service
to view a list of services that have been started:systemctl list-unit-files|grep enabled
to view a list of services that failed to start:systemctl --failed

PS：使用命令 systemctl is-enabled postfix.service 得到的值可以是enable、disable或static，这里的 static 它是指对应的 Unit 文件中没有定义[Install]区域，因此无法配置为开机启动服务。 


Description: The Enable service is in the current "runlevel" configuration file directory/etc/systemd/system/multi-user.target.wants/, establish/usr/lib/systemd/ A soft link within the system that corresponds to a service profile; Disabling a service is removing this soft link, adding a service is adding a soft connection

Turn on SVN self-booting:

# Systemctl Enable Svnserve.service

Usage of Systemctl in RHEL 7