在 Linux Bash Shell 中，$* 和 [email protected] 都表示引數列表中的所有引數，它們在具體使用中會有哪些不同呢？這裡我們可以寫一個 Shell 指令碼做實驗：

#!/bin/bash

# This script is to verify the difference between $* and [email protected]

echo Dollar Star is $*
echo "Dollar Star in double quotes is $*"

echo Dollar At is [email protected]
echo "Dollar At in double quotes is 
 
[email protected]"

echo 
echo "Looping through Dollar Star"
for i in $*
do
	echo "parameter is $i"
done
echo 
echo "Looping through Dollar Star with double quotes"
for i in "$*"
do
	echo "Parameter is $i"
done 

echo
echo "Looping through Dollar At"
for i in [email protected]
do
	echo "Parameter is $i"
done
echo
echo "Looping through Dollar At with double quotes"
for i in "
 
[email protected]"
do
	echo "Parameter is $i"
done

# chmod 755 star.sh 

# ./star.sh 1 "2  3 " 4   5

Dollar Star is 1 2 3 4 5
Dollar Star in double quotes is 1 2  3  4 5
Dollar At is 1 2 3 4 5
Dollar At in double quotes is 1 2  3  4 5

Looping through Dollar Star
parameter is 1
parameter is 2
parameter is 3
parameter is 4
parameter is 5

Looping through Dollar Star with double quotes
Parameter is 1 2  3  4 5

Looping through Dollar At
Parameter is 1
Parameter is 2
Parameter is 3
Parameter is 4
Parameter is 5

Looping through Dollar At with double quotes
Parameter is 1
Parameter is 2  3 
Parameter is 4
Parameter is 5
 

1、直接輸出不保留空格

2、帶雙引號輸出會保留帶引號的空格

3、不帶雙引號迴圈遍歷的輸出結果一樣：每個字串單獨輸出

不同點如下：

1、帶雙引號遍歷$*相當於帶雙引號輸出$*

2、帶雙引號遍歷[email protected]分別輸出每個引數，帶雙引號的引數保留空格輸出