read 指令詳解

read 指令從标準輸入中讀取一行，并把輸入行的每個字段的值指定給 shell 變量

文法選項

-p  read –p “提示語句”，則螢幕就會輸出提示語句，等待輸入，并将輸入存儲在REPLY中
-n  read –n 個數
-t  read –t 時間
-s  read -s 選項能夠使read指令中輸入的資料不顯示在螢幕上           

例子

1. 從标準輸入讀取輸入并指派給變量

[xiess@layzj022301 ~]$ read readfile
hello,world!!welcome to shell
[xiess@layzj022301 ~]$ echo $readfile
hello,world!!welcome to shell
[xiess@layzj022301 ~]$           

1. 等待一組輸入，每個單詞之間使用空格隔開，直到回車結束，并分别将單詞依次指派給這三個讀入變量。

[xiess@layzj022301 ~]$ read frist second third
the_one the_two the_three
[xiess@layzj022301 ~]$ echo "$frist" "$second" "$third"
the_one the_two the_three
[xiess@layzj022301 ~]$           

1. REPLY示例

[xiess@layzj022301 ~]$ read -p "Enter your name: "
Enter your name: admin_xiess
[xiess@layzj022301 ~]$ echo $REPLY
admin_xiess
[xiess@layzj022301 ~]$           

1. 關閉顯示

[root@cinder01 ~]# cat readfile.sh 
#!/bin/bash
read -s -p "Enter your password: " password
echo
echo "your password is $password"
[root@cinder01 ~]# chmod a+x readfile.sh 
[root@cinder01 ~]# sh readfile.sh 
Enter your password: 
your password is 123456