一、获取用户输入

1、基本读取

read命令接收标准输入的输入，或其它文件描述符的输入。得到输入后，read命令将数据输入放入一个标准变量中。

[root@rac2 ~]# cat t8.sh

#!/bin/bash

#testing the read command

echo -n "enter your name:" ---：-n用于允许用户在字符串后面立即输入数据，而不是在下一行输入。

read name

echo "hello $name ,welcome to my program."

[root@rac2 ~]# ./t8.sh

enter your name:zhou

hello zhou ,welcome to my program.

read命令的-p选项，允许在read命令行中直接指定一个提示：

[root@rac2 ~]# cat t9.sh

#!/bin/bash

#testing the read -p option

read -p "please enter your age:" age ---age与前面必须有空格

echo "your age is $age"

[root@rac2 ~]# ./t9.sh

please enter your age:10

your age is 10

2、在read命令中也可以不指定变量，如果不指定变量，那么read命令会将接收到的数据防止在环境变量REPLAY中

[root@rac2 ~]# cat t10.sh

#!/bin/bash

#tesing the replay environment variable

read -p "enter a number:"

factorial=1

for (( count=1; count<=$REPLY; count++ ))

do

factorial=$[ $factorial * $count ]

done

echo "the factorial of $REPLY is $factorial"

[root@rac2 ~]# ./t10.sh

enter a number:5

the factorial of 5 is 120

3、计时

-t选项指定read命令等待输入的秒数。当计时器计时数满时，read命令返回一个非零退出状态

[root@rac2 ~]# cat t11.sh

#!/bin/bash

#timing the data entry

if read -t 5 -p "please enter your name:" name

then

echo "hello $name ,welcome to my script"

else

echo "sorry ,tow slow!"

fi

[root@rac2 ~]# ./t11.sh

please enter your name:zhou

hello zhou ,welcome to my script

[root@rac2 ~]# ./t11.sh

please enter your name:sorry ,tow slow!

4、默读

有时候需要脚本用户进行输入，但不希望输入的数据显示在监视器上，（实际上是显示的只是read命令将文本颜色设置为与背景相同的了）。

[root@rac2 ~]# cat t12.sh

#!/bin/bash

#hiding input data from the monitor

read -s -p "enter your password:" pass

echo "is your password really $pass?"

[root@rac2 ~]# ./t12.sh

enter your password:is your password really 12345?

5、读取文件

每调用一次read命令都会读取文件中的一行文本，当文件中没有可读的行时，read命令将以非零退出状态退出。

[root@rac2 ~]# cat t13.sh

#!/bin/bash

count=1

cat test | while read line

do

echo "line $count:$line"

count=$[$count + 1]

done

[root@rac2 ~]# ./t13.sh

line 1:zhou

line 2:xiao

line 3:zhou