SYSTEMd common component description

systemd To optimize the service Only the disadvantages of linear service . Here is a note about the functions of some common components , Know which to use when you want to do something . Do not record the writing of the command in detail .

• systemctl

systemd Master order , For management system , It can be restarted 、halt、 Rescue mode, etc .

• systemd-analyze

Analyze the service startup time .

• hostnamectl

see / Set the current host information .

• localectl

see / Set localization related information .

• timedatectl

see / Set time zone related information .

• loginctl

View current user information .

• journalctl

Log management , The configuration file for the log is /etc/systemd/journald.conf

You can see / Set the log information and storage method .

Support customized viewing in various ways , Including viewing user status / Kernel mode 、 At a certain time 、 Number of specific rows 、 Specific users, etc .

Unit：

every last unit In fact, it can be understood as a service, All have a profile . For the writing method of configuration file, please refer to https://www.freedesktop.org/software/systemd/man/systemd.unit.html

unit adopt systemctl Command to control .

• enable

Enable service , To be exact, it means getting the service to /etc/systemd/system Under the table of contents , Make it readable . It is equivalent to activation of startup .

• disable

Disable service ,enable The inverse .

• list-units

View the current units The state of , You can view various statuses （ Boot failure 、 Configuration file not found ）.

• status

Look at the individual unit state .

• start
• stop
• restart
• kill
• show
• reload

Overloaded single unit The configuration file .

• daemon-reload

Reload all changed configuration files .

• set-property

Modify a unit The specified parameters in the configuration .

• list-dependency

Make a list of unit All dependencies of .

• list-unit-files

List all profiles , You can view the status of the corresponding configuration file .