在MySQL數據庫部署的過程中，在安裝了MySQL軟件，並配置了my.cnf配置文件後，需要創建MySQL實例。
MySQL 5.5實例創建完成了，默認會有登陸用戶名和密碼爲空的用戶，一般需要修改root用戶密碼，並刪除無效用戶，然後才能提供給應用使用。
這個過程可以通過shell腳本自動完成實例創建，啓動，自動生成密碼，修改root用戶密碼，刪除無效用戶。
shell腳本有多種編寫方法，我編寫的shell腳本如下：
#!/bin/bash
# this scripts used to initial the mysql instance and modify password
# created by zhaofx
# MySQL software directory.
readonly SYMLINK='/usr/local/mysql'
echo "MySQL的軟件安裝目錄爲${SYMLINK}"
# MySQL database port
readonly MYSQL_PORT=3306
echo "MySQL實例的端口爲${MYSQL_PORT}"
# MySQL database directory.
readonly MYSQL_DATA_DIR="/data/mysql_${MYSQL_PORT}"
echo "MySQL的實例數據文件目錄爲${MYSQL_DATA_DIR}"
echo "準備創建MySQL實例"
cd $SYMLINK
./scripts/mysql_install_db --user=mysql --basedir=/usr/local/mysql --datadir=${MYSQL_DATA_DIR}/data
echo "開始啓動數據庫實例，修改root用戶密碼，刪除無效用戶"
echo ""
cp /etc/my.cnf /data/mysql_${MYSQL_PORT}/my.cnf
echo "Startup MySQl Service:localhost_"${MYSQL_PORT}
/usr/local/mysql/bin/mysqld_safe --defaults-file=/data/mysql_${MYSQL_PORT}/my.cnf &
echo ""
# MySQL root password
# 隨機生成八位密碼，作爲MySQL的密碼
for i in {1..10}
do
A=`head -c 500 /dev/urandom | tr -dc a-zA-Z | tr [a-z] [A-Z]|head -c 1`
B=`head -c 500 /dev/urandom | tr -dc a-z0-9A-Z | head -c 6`
C=`echo $RANDOM|cut -c 2`
echo $A$B$C > /home/mysql/.password_mysql
done
readonly MYSQL_ROOT_PASS=$A$B$C
echo "MySQL實例的root用戶密碼已經生成"
su - mysql <<EOF
/usr/local/mysql/bin/mysql -uroot -S /data/mysql_${MYSQL_PORT}/tmp/mysql.sock -e "select user,host from mysql.user;"
/usr/local/mysql/bin/mysqladmin -uroot -S /data/mysql_${MYSQL_PORT}/tmp/mysql.sock password "${MYSQL_ROOT_PASS}"
EOF
echo "MySQL的root用戶密碼已經修改"
echo ""
/usr/local/mysql/bin/mysql -uroot -p${MYSQL_ROOT_PASS} -S /data/mysql_${MYSQL_PORT}/tmp/mysql.sock -e "delete from mysql.user where user='';delete from mysql.user where user='root' and host!='localhost'; FLUSH PRIVILEGES;"
/usr/local/mysql/bin/mysql -uroot -p${MYSQL_ROOT_PASS} -S /data/mysql_${MYSQL_PORT}/tmp/mysql.sock -e "delete from mysql.db where db='test' or db='test\\_%'; FLUSH PRIVILEGES;"
echo "MySQL實例啓動成功，初始用戶環境修改完畢"
echo ""
/usr/local/mysql/bin/mysql -uroot -p${MYSQL_ROOT_PASS} -S /data/mysql_${MYSQL_PORT}/tmp/mysql.sock -e " show databases;"
/usr/local/mysql/bin/mysql -uroot -p${MYSQL_ROOT_PASS} -S /data/mysql_${MYSQL_PORT}/tmp/mysql.sock -e " select user,host from mysql.user;" 大家可以參考！