shell script中read的用法

1、read基本读取

#!/bin/bash  
#testing the read command  
  
echo -n "Enter you name:"   #echo -n 让用户直接在后面输入   
read name  #输入的多个文本将保存在一个变量中  
echo "Hello $name, welcome to my progra  

执行：

# ./read.sh  
Enter you name: yuan  
Hello yuan, welcome to my program  　

2、read -p (直接在read命令行指定提示符) 

#!/bin/bash  
#testing the read -p option  
read -p "Please enter your age: " age  
days=$[ $age * 365 ]  
echo "That makes you over $days days old!"  

3、read -p（指定多个变量）

#!/bin/bash  
# entering multiple variables  
  
read -p "Enter your name:" first last  
echo "Checking data for $last, $first"  

执行： 

 

# ./read1.sh  
Enter your name: a b  
Checking data for b, a  

4、超时、等待输入的秒数（read -t）

#!/bin/bash  
# timing the data entry  
  
if read -t 5 -p "Please enter your name: " name     #记得加-p参数， 直接在read命令行指定提示符  
then  
    echo "Hello $name, welcome to my script"  
else  
    echo   
    echo "Sorry, too slow!"  
fi  

执行：

# ./read3.sh  
Please enter your name:   
Sorry, too slow!  
  
  
# ./read3.sh   
Please enter your name: wang  
Hello wang, welcome to my script  

5、read命令对于输入字符的判断

• []有比较的判断的功能
• -o代表or
• &&在shell中的用法是如果&&左边的命令执行成功（即$?=0）时才能执行&&右边的命令

#!/bin/bash  
  
  
read -p "Please input(Y/N):" yn  
[ "$yn" == "Y" -o "$yn" == "y" ]&&echo  "OK,continue"&&exit 0  
[ "$yn" == "N" -o "$yn" == "n" ]&&echo "Oh,interrupt!"&&exit 0  
echo "i don't konw what your choice is"&&exit 0  

　执行：

yuanqiangfei@ubuntu:~/script$ ./sh01.sh   
Please input(Y/N):y  
OK,continue  
yuanqiangfei@ubuntu:~/script$ ./sh01.sh   
Please input(Y/N):n  
Oh,interrupt!  

6、隐藏方式读取（read -s）

• 在中括号 [] 内的每个组件都需要有空白键来分隔；
• 在中括号内的变量，最好都以双引号括号起来；
• 在中括号内的常数，最好都以单或双引号括号起来。
• ==和！=两边都要有空格
• []有比较的判断的功能 

#!/bin/bash  
#entering muiltple variables  
  
while true  
do  
        read -s -p "Please enter your password:"  passwd  
  
        [ "$passwd" == "123456" ]&&echo "password is right!"&&exit 0  
        [ "$passwd" != "123456" ]&&echo "password is not right,Please input again!"&&continue  
done  

执行：

yuanqiangfei@ubuntu:~/script$ ./read.sh   
Please enter your password:password is right!  
yuanqiangfei@ubuntu:~/script$ ./read.sh   
Please enter your password:password is not right,Please input again!  
Please enter your password:  

7、从文本中读取

 

#!/bin/bash  
# reading data from a file  
  
count=1  
cat test | while read line  
do  
   echo "Line $count: $line"  
   count=$[ $count + 1 ]  
done  
echo "Finished processing the file"  

执行结果：

 ./read6.sh  
Line 1: The quick brown dog jumps over the lazy fox.  
Line 2: This is a test, this is only a test.  
Line 3: O Romeo, Romeo! Wherefore art thou Romeo?  
Finished processing the file