基本用法 read命令主要用於從標準輸入讀取內容或從文件中讀取內容，並把信息保存到變數中。其常用用法如下所示： | 選項 | 解釋 | | | | | a array | 將內容讀取到數值中，變數預設為數組且以空格做為分割符 | | d delimiter | 遇到指定的 ...
基本用法
read命令主要用於從標準輸入讀取內容或從文件中讀取內容，並把信息保存到變數中。其常用用法如下所示：
read [選項] [文件]| 選項 | 解釋 |
|---|---|
| -a array | 將內容讀取到數值中，變數預設為數組且以空格做為分割符 |
| -d delimiter | 遇到指定的字元即停止讀取 |
| -n nchars | 指定最多可以讀入的字元數，即定義輸入文本的長度 |
| -r | 屏蔽轉義符 |
| -p prompt | 顯示提示信息 |
| -s | 靜默模式，在輸入字元時不在終端中顯示，常用於密碼輸入等 |
| -t timeout | 指定超時時間 |
| -u FD | 從文件描述符中讀入，該FD可以由exec開啟 |
用法示例
1、從標準輸入讀入
[root@localhost test]# cat read.sh
#!/bin/bash
echo -n "Please input your name:"
read name
echo "Hello $name"
[root@localhost test]# bash read.sh
Please input your name:Jack
Hello Jack2、指定顯示信息從標準輸入讀入
[root@localhost test]# cat read.sh
#!/bin/bash
# echo -n "Please input your name:"
read -p "Please input your name:" name
# read name
echo "Hello $name"
[root@localhost test]# bash read.sh
Please input your name:Jack
Hello Jack在以上示例中，read是一次可以接受多個參數的，如下所示：
read -p "Please input your name:" firstName secondName lastName但需要註意的事項如下：
- 如果輸入的數據少於變數個數，則多餘的變數不會獲取到數據，即變數值為空
- 如果輸入的數據多於變數個數，則超出的數據將全部賦給最後一個變數
- 如果在read命令後面沒有定義任何變數，腳本在執行時，如果用戶輸入數據，此時數據則保存到環境變數$REPLY中
3、指定超時時間
[root@localhost test]# cat read.sh
#!/bin/bash
if read -t 3 -p "Please input your name:" firstName secondName lastName
then
echo "variable is $firstName - $secondName - $lastName"
else
echo -e "\ntimeout\n"
fi
[root@localhost test]# bash read.sh
Please input your name:
timeout4、從指定文件中讀取內容
[root@localhost test]# cat -n test.txt
1 this is test text.
2 this is second line.
3 Hello world
4 C# Main
5 Python
# 使用-u選項
[root@localhost test]# cat readtest.sh
#!/bin/bash
exec 5< ~/test/test.txt
count=0
while read -u 5 var
do
let count=$count+1
echo "Line $count is $var"
done
echo "Total line count is $count"
exec 5<&-
[root@localhost test]# bash readtest.sh
Line 1 is this is test text.
Line 2 is this is second line.
Line 3 is Hello world
Line 4 is C# Main
Line 5 is Python
Total line count is 5
# 使用管道
[root@localhost test]# cat readtest.sh
#!/bin/bash
count=1
cat ~/test/test.txt | while read line
do
echo "Current line $count - $line "
let count=$count+1
done
echo "Total line count is $count"
[root@localhost test]# bash readtest.sh
Current line 1 - this is test text.
Current line 2 - this is second line.
Current line 3 - Hello world
Current line 4 - C# Main
Current line 5 - Python
Total line count is 1
# 使用重定向
[root@localhost test]# cat readtest.sh
#!/bin/bash
count=0
while read line
do
let count=$count+1
echo "Current line $count - $line "
done < ~/test/test.txt
echo "Total line count is $count"
[root@localhost test]# bash readtest.sh
Current line 1 - this is test text.
Current line 2 - this is second line.
Current line 3 - Hello world
Current line 4 - C# Main
Current line 5 - Python
Total line count is 5本文同步在微信訂閱號上發佈，如各位小伙伴們喜歡我的文章，也可以關註我的微信訂閱號：woaitest，或掃描下麵的二維碼添加關註：
