linux systemctl 常用用法简介

主要介绍systemctl的几个功能如下：

1.查看某个服务的状态

2.关闭某个服务

3.开启某个服务

4.设置某个为开机自启动

5.关闭某个服务为开机不启动

6.查看所有开启启动的服务

1.查看某个服务的状态

用法:systemctl status 需要查询的服务 例如 mariadb.service 注意Actice[root@localhost linux]# systemctl status mariadb.service
● mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
   Active: -- :: EDT; 19min ago
  Process:  ExecStartPost=/usr/libexec/mariadb-/SUCCESS)
  Process:  ExecStartPre=/usr/libexec/mariadb-prepare-db-/SUCCESS)
 Main PID:  (mysqld_safe)
   CGroup: /system.slice/mariadb.service
           ├─ /bin/sh /usr/bin/mysqld_safe --basedir=/usr
           └─ /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/...

May  :: localhost.localdomain systemd[]: Starting MariaDB database server...
May  :: localhost.localdomain mysqld_safe[]:  :: mysqld_safe Logging to '/var/log...g'.
May  :: localhost.localdomain mysqld_safe[]:  :: mysqld_safe Starting mysqld daem...sql
May  :: localhost.localdomain systemd[]: Started MariaDB database server.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost linux]# 

其实查看状态还可以用ps查询

ps aux 是查询所有进程grep是提取需要的行[root@localhost linux]# ps aux | grep mariadb
mysql         ?        Sl   :   : /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --log-error=/var/log/mariadb/mariadb.log --pid-file=/var/run/mariadb/mariadb.pid --socket=/var/lib/mysql/mysql.sock
root            pts/    S+   :   : grep --color=auto mariadb
[root@localhost linux]#

2.关闭某个服务

[root@localhost linux]# systemctl stop mariadb.service
[root@localhost linux]# 再次查看其状态 可见 已经关闭完成了[root@localhost linux]# ps aux | grep -v grep | grep mariadb.service[root@localhost linux]# 

3.开启某个服务

[root@localhost linux]# systemctl start mariadb.service
[root@localhost linux]#
查看服务是否启动
[root@localhost linux]# ps aux | grep mariadb
mysql         ?        Sl   :   : /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --log-error=/var/log/mariadb/mariadb.log --pid-file=/var/run/mariadb/mariadb.pid --socket=/var/lib/mysql/mysql.sock
root            pts/    S+   :   : grep --color=auto mariadb
[root@localhost linux]#
[root@localhost linux]#
[root@localhost linux]# ps aux | grep mariadb | grep -v grep
mysql         ?        Sl   :   : /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --log-error=/var/log/mariadb/mariadb.log --pid-file=/var/run/mariadb/mariadb.pid --socket=/var/lib/mysql/mysql.sock

4.设置某个服务为开机自启动

[root@localhost linux]# systemctl is-enabled mariadb.service
enabled
[root@localhost linux]# 

5.关闭某个服务为开机不启动

[root@localhost linux]# systemctl disable mariadb.service
Removed symlink /etc/systemd/system/multi-user.target.wants/mariadb.service.
[root@localhost linux]# 

6.查看所有开启启动的服务

[root@localhost linux]# ls /etc/systemd/system/multi-user.target.wants/
abrt-ccpp.service    auditd.service      kdump.service           postfix.service   sysstat.service
abrtd.service        chronyd.service     libstoragemgmt.service  remote-fs.target  tuned.service
abrt-oops.service    crond.service       mdmonitor.service       rngd.service      vmtoolsd.service
abrt-vmcore.service  cups.path           ModemManager.service    rsyslog.service   vsftpd.service
abrt-xorg.service    cups.service        NetworkManager.service  smartd.service
atd.service          irqbalance.service  nfs-client.target       sshd.service
[root@localhost linux]# 

可见，刚刚禁止之后，这个文件中就没有了mariadb.service[root@localhost linux]# ls /etc/systemd/system/multi-user.target.wants/mariadb.servicels: cannot access /etc/systemd/system/multi-user.target.wants/mariadb.service: No such file or directory[root@localhost linux]# 

现在利用systemctl将mariadb.service设置为开机自启动[root@localhost linux]# systemctl enable mariadb.serviceCreated symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service.[root@localhost linux]# 

再次写ls语句[root@localhost linux]# ls /etc/systemd/system/multi-user.target.wants/mariadb.service/etc/systemd/system/multi-user.target.wants/mariadb.service[root@localhost linux]#