systemctlcentosfedora用法

LinuxSystemctl是一个系统管理守护进程、工具和库的集合&＃xff0c;用于取代System V、service和chkconfig命令&＃xff0c;初始进程主要负责控制systemd系统和服务管理器。通过Systemctl –help可以看到该命令主要分为&＃xff1a;查询或发送控制命令给systemd服务&＃xff0c;管理单元服务的命令&＃xff0c;服务文件的相关命令&＃xff0c;任务、环境、快照相关命令&＃xff0c;systemd服务的配置重载&＃xff0c;系统开机关机相关的命令。

1. 列出所有可用单元

# systemctl list-unit-files

2. 列出所有运行中单元

# systemctl list-units

3. 列出所有失败单元

# systemctl –failed

4. 检查某个单元&＃xff08;如 crond.service&＃xff09;是否启用

# systemctl is-enabledcrond.service

5. 列出所有服务

# systemctl list-unit-files –type&＃61;service

6. Linux中如何启动、重启、停止、重载服务以及检查服务&＃xff08;如 httpd.service&＃xff09;状态

# systemctl start httpd.service

# systemctl restart httpd.service

# systemctl stop httpd.service

# systemctl reload httpd.service

# systemctl status httpd.service

注意&＃xff1a;当我们使用systemctl的start&＃xff0c;restart&＃xff0c;stop和reload命令时&＃xff0c;终端不会输出任何内容&＃xff0c;只有status命令可以打印输出。

7. 如何激活服务并在开机时启用或禁用服务&＃xff08;即系统启动时自动启动mysql.service服务&＃xff09;

# systemctl is-active mysql.service

# systemctl enable mysql.service

# systemctl disable mysql.service

8. 如何屏蔽&＃xff08;让它不能启动&＃xff09;或显示服务&＃xff08;如ntpdate.service&＃xff09;

# systemctl mask ntpdate.service

ln -s ‘/dev/null”/etc/systemd/system/ntpdate.service’

# systemctl unmask ntpdate.service

rm ‘/etc/systemd/system/ntpdate.service’

9. 使用systemctl命令杀死服务

# systemctl killcrond

10. 列出所有系统挂载点

# systemctl list-unit-files –type&＃61;mount

11. 挂载、卸载、重新挂载、重载系统挂载点并检查系统中挂载点状态

# systemctl start tmp.mount

# systemctl stop tmp.mount

# systemctl restart tmp.mount

# systemctl reload tmp.mount

# systemctl status tmp.mount

12. 在启动时激活、启用或禁用挂载点&＃xff08;系统启动时自动挂载&＃xff09;

# systemctl is-active tmp.mount

# systemctl enable tmp.mount

# systemctl disable tmp.mount

13. 在Linux中屏蔽&＃xff08;让它不能启用&＃xff09;或可见挂载点

# systemctl mask tmp.mount

ln -s ‘/dev/null”/etc/systemd/system/tmp.mount’

# systemctl unmask tmp.mount

rm ‘/etc/systemd/system/tmp.mount’

14. 列出所有可用系统套接口

# systemctl list-unit-files –type&＃61;socket

15. 检查某个服务的所有配置细节

# systemctl showmysql

16. 获取某个服务&＃xff08;httpd&＃xff09;的依赖性列表

# systemctl list-dependencies httpd.service

17. 启动救援模式

# systemctl rescue

18. 进入紧急模式

# systemctl emergency

19. 列出当前使用的运行等级

# systemctl get-default

20. 启动运行等级5&＃xff0c;即图形模式

# systemctl isolate runlevel5.target

或

# systemctl isolate graphical.target

21. 启动运行等级3&＃xff0c;即多用户模式&＃xff08;命令行&＃xff09;

# systemctl isolate runlevel3.target

或

# systemctl isolate multiuser.target

22. 设置多用户模式或图形模式为默认运行等级

# systemctl set-default runlevel3.target

# systemctl set-default runlevel5.target

23. 重启、停止、挂起、休眠系统或使系统进入混合睡眠

# systemctl reboot

# systemctl halt

# systemctl suspend

# systemctl hibernate

# systemctl hybrid-sleep

对于不知运行等级为何物的人&＃xff0c;说明如下。

Runlevel 0 : 关闭系统

Runlevel 1 : 救援&＃xff0c;维护模式

Runlevel 3 : 多用户&＃xff0c;无图形系统

Runlevel 4 : 多用户&＃xff0c;无图形系统

Runlevel 5 : 多用户&＃xff0c;图形化系统

Runlevel 6 : 关闭并重启机器