mysqladmin status command
mysqladmin status
MySQL show status command to see open database connections example
mysql> show status like 'Conn%';
See the number of currently open connections
mysql> show status like '%onn%';
Use show processlist sql command to see the number of open connections
mysql> show processlist;
Use netstat or ss command to list open database connections
netstat -nat | grep :3306
Source: https://www.cyberciti.biz/faq/howto-show-mysql-open-database-connections-on-linux-unix/