把mysql查询结果保存到文件的shell脚本

该脚本是先删除已经存在的文件，然后后台执行sql语句将其执行结果以一定的格式写入文件

#!/bin/bash
if [ -f "/var/lib/mysql/hell.txt" ]; then
rm -f /var/lib/mysql/hell.txt
echo "delete /var/lib/mysql/hell.txt" >> hell.txt
fi
mysql -uroot -plab <<eof
use home;
select yonghuid,xueyuanid into outfile './hell.txt' fields terminated by '|' lines terminated by '\r\n' from sns_home_user where yonghuid < 20;
eof