linux 定期自动备份mysql的shell

数据无价，及时备份
刚才有个玩家在站上玩游戏，提醒了我要及时备份数据啊，万一哪天服务器挂了把他们的数据丢了，我可就是罪人了！
一直打算放个自动备份的shell，都没有放。正好现在不忙，随手加了进去。
安全起见，直接用Root执行的：
/root/mysql_backup.sh

# everyday 3:00 AM execute database backup
3 0 * * * /root/mysql_backup.sh

以下是自动自动备份shell，只保留最新5天

#!/bin/sh  
# mysql_backup.sh: backup mysql databases and keep newest 5 days backup.  
#  
# db_user is mysql username  
# db_passwd is mysql password  
# db_host is mysql host  
# —————————–  
db_user="root"  
db_passwd="zhoz.com"  
db_host="localhost"  
 
# the directory for story your backup file.  
backup_dir="/home/zhozdbbackup"  
 
# date format for backup file (dd-mm-yyyy)  
time="$(date +"%d-%m-%Y")"  
 
# mysql, mysqldump and some other bin's path  
MYSQL="/usr/bin/mysql"  
MYSQLDUMP="/usr/bin/mysqldump"  
MKDIR="/bin/mkdir"  
RM="/bin/rm"  
MV="/bin/mv"  
GZIP="/bin/gzip"  
 
# check the directory for store backup is writeable  
test ! -w $backup_dir && echo "Error: $backup_dir is un-writeable." && exit 0  
 
# the directory for story the newest backup  
test ! -d "$backup_dir/backup.0/" && $MKDIR "$backup_dir/backup.0/"  
 
# get all databases  
all_db="$($MYSQL -u $db_user -h $db_host -p$db_passwd -Bse 'show databases')"  
for db in $all_db  
do  
$MYSQLDUMP -u $db_user -h $db_host -p$db_passwd $db | $GZIP -9 > "$backup_dir/backup.0/$time.$db.gz"  
done  
 
# delete the oldest backup  
test -d "$backup_dir/backup.5/" && $RM -rf "$backup_dir/backup.5"  
 
# rotate backup directory  
for int in 4 3 2 1 0  
do  
if(test -d "$backup_dir"/backup."$int")  
then  
next_int=`expr $int + 1`  
$MV "$backup_dir"/backup."$int" "$backup_dir"/backup."$next_int"  
fi  
done  
exit 0;