一般情况下，我们想要进入mysql命令模式总是需要按如下交互输入密码确认，才能进入命令行模式：
zhanhailiang@linux-06bq:~> mysql -u sl -p
enter password:
其实我们完全可以使用expect编写脚本，来通来expect与shell交互通信来实现免密码登录：
zhanhailiang@linux-06bq:~> cat mysql.sh
#!/usr/local/bin/expect
spawn /usr/local/services/mysql/bin/mysql -u sl -p
expect {
assword { send slr }
}
interact
其实这段脚本的意思就是说“执行/usr/local/services/mysql/bin/mysql -u sl -p，等待响应，若匹配assword，则发送sl(即mysql用户登录密码)，回车，，模拟用户手工操作”。
编写完mysql.sh脚本后，赋予执权限，然后就可以通过执行mysql.sh来免密码进入mysql命令行模式。
zhanhailiang@linux-06bq:~> chmod +x mysql.sh
zhanhailiang@linux-06bq:~> ./mysql.sh
spawn /usr/local/services/mysql/bin/mysql -u sl -p
enter password:
welcome to the mysql monitor. commands end with ; or g.
your mysql connection id is 12912
server version: 5.5.14-log mysql community server (gpl)
copyright (c) 2000, 2010, oracle and/or its affiliates. all rights reserved.
oracle is a registered trademark of oracle corporation and/or its
affiliates. other names may be trademarks of their respective
owners.
type 'help;' or 'h' for help. type 'c' to clear the current input statement.
mysql>
注：expect拥有众多的参数及丰富的应用场景，有兴趣的同学请自行查看man手册或其它资料。