[Linux 常見問題] Shell - Does linux shell support list data structure?

Source From Here 
Question 
I know lots of script language support list structure, such as python, python, ruby, and javascript, so what about linux shell? does shell support such syntax? 

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1. for i in list:  
2. do  
3.      print i  
4. done  

How-To 
It supports lists, but not as a separate data structure (ignoring arrays for the moment). The for loop iterates over a list (in the generic sense) of white-space separated values, regardless of how that list is created, whether literally: 

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1. for i in 1 2 3; do  
2.     echo "$i"  
3. done  

or via parameter expansion: 

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1. listVar="1 2 3"  
2. for i in $listVar; do  
3.     echo "$i"  
4. done  

or command substitution: 

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1. for i in $(echo 1; echo 2; echo 3); do  
2.     echo "$i"  
3. done  

An array is just a special parameter which can contain a more structured list of value, where each element can itself contain whitespace. Compare the difference: 

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1. #!/bin/sh  
2. array=("item 1" "item 2" "item 3")  
3. lp=0  
4. echo -e "\t[Info] Correct:"  
5. for i in "${array[@]}"; do   # The quotes are necessary here  
6.     lp=$((lp+1))  
7.     echo -e "\t$lp=$i"  
8. done  
9.   
10. list='"item 1" "item 2" "item 3"'  
11. lp=0  
12. echo -e "\t[Info] Test1:"  
13. for i in $list; do  
14.     lp=$((lp+1))  
15.     echo -e "\t$lp=$i"  
16. done  
17.   
18. lp=0  
19. echo -e "\t[Info] Test2:"  
20. for i in "$list"; do  
21.     lp=$((lp+1))  
22.     echo -e "\t$lp=$i"  
23. done  
24.   
25. lp=0  
26. echo -e "\t[Info] Test3:"  
27. for i in ${array[@]}; do  
28.     lp=$((lp+1))  
29.     echo -e "\t$lp=$i"  
30. done  

Execution result: 

# ./test.sh
[Info] Correct:
1=item 1
2=item 2
3=item 3
[Info] Test1:
1="item
2=1"
3="item
4=2"
5="item
6=3"
[Info] Test2:
1="item 1" "item 2" "item 3"
[Info] Test3:
1=item
2=1
3=item
4=2
5=item
6=3

Supplement 
* nixCraft - Bash For Loop Examples