方法二：使用mysql参数的方法
mysql -u$user -p$pass -D $db -e "select host from user;"
当然，可以通过将传参的方式来传递 -e 后面的语句。
使用示例：
cat count_tb_post_fourhour.sh
#!/bin/bash count_tb_post_fourhour_keys=`/usr/bin/mysql -hrr-bp1************.mysql.rds.aliyuncs.com -uzh*****ng -p******** -D dee****hion -e "select count(1) from tb_post where created_at > date_sub(now(), interval 4 hour) and platformId = 1;" >& |grep -v "Warning: Using a password"|grep -v "count";` echo $count_tb_post_fourhour_keys [root@weifeng scripts]# sh count_tb_post_fourhour.sh