mysql_replication []

show slave status \G

Important to look out for:

Slave_IO_Running: Yes
Slave_SQL_Running: No

The following means that the master and slave are communicating. The master is sending over the IO commands and the slave is receiving them

Slave_IO_Running: Yes

The Slave is NOT running the IO commands sent from the Master

Slave_SQL_Running: No

mysql -e 'show slave status\G'|grep -i behind

mysql -e 'SHOW SLAVE STATUS\G;' | grep -i slave*running