shell脚本(4)-格式化输入

一、read命令

1、概念：

默认接受键盘的输入，回车符代表输入结束

2、read命令选项

-p：打印信息

-t：限定时间

-s：不回显

-n：输入字符个数

3、举例说明

（1）模拟登录

[root@localhost test20210724]# vi read_command_study.sh

#!usr/bin/bash
clear
echo -n -e "Login: "
read acc
echo -n -e "Password: "
read pw
echo "account:$acc password:$pw"

查看运行结果：

[root@localhost test20210724]# sh read_command_study.sh 
Login: root
Password: 123
account:root password:123

（2）优化：read -s  #不显示密码

[root@localhost test20210724]# vi read_command_study.sh 

#!usr/bin/bash
clear
echo -n -e "Login: "
read acc
echo -n -e "Password: "
read -s pw
echo
echo "account:$acc password:$pw"

查看运行结果：

[root@localhost test20210724]# sh read_command_study.sh 
Login: root
Password: 
account:root password:123

（3）优化：read -t5 #增加5秒超时，5秒不输入退出

[root@localhost test20210724]# vi read_command_study.sh 

#!usr/bin/bash
clear
echo -n -e "Login: "
read acc
echo -n -e "Password: "
read -s -t5  pw
echo
echo "account:$acc password:$pw"

查看运行结果：

[root@localhost test20210724]# sh read_command_study.sh 
Login: root
Password: 
account:root password:

（4）优化：read -n6 #密码只识别6位，超过6位自动输出完成

[root@localhost test20210724]# vi read_command_study.sh 

#!usr/bin/bash
clear
echo -n -e "Login: "
read acc
echo -n -e "Password: "
read -s -t5 -n6 pw
echo
echo "account:$acc password:$pw"

查看运行结果：

[root@localhost test20210724]# sh read_command_study.sh 
Login: root
Password: 
account:root password:123456

（5）优化：read -p "Login: " acc #read并且打印输出

[root@localhost test20210724]# vi read_command_study.sh 

#!usr/bin/bash
clear
read -p "Login: " acc
read -s -t5 -n6 -p "Password: " pw
echo
echo "account:$acc password:$pw"

查看运行结果：

[root@localhost test20210724]# sh read_command_study.sh 
Login: root
Password: 
account:root password:123