查看MySQL是否在运行

可以使用以下命令来检查MySQL是否在运行：

sudo systemctl status mysql

如果MySQL正在运行，您将看到类似以下内容的输出：

● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2022-01-13 17:32:10 UTC; 1 day  ago
 Main PID: 1234 (mysqld)
    Tasks: 34 (limit: 2359)
   Memory: 332.7M
   CGroup: /system.slice/mysql.service
           └─1234 /usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid

如果MySQL没有在运行，您将看到类似以下内容的输出：

● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Thu 2022-01-13 17:32:10 UTC; 1 day ago
 Main PID: 1234 (code=exited, status=0/SUCCESS)

如果MySQL没有运行，您可以使用以下命令启动它：

sudo systemctl start mysql