While loop "Go" in the shell

Turn from: Http://blog.chinaunix.net/uid-25880122-id-2901409.htmlwhile loop format

1. While expression
2. Do
3. Command
4. Command
5. ```
6. Done

1. The counter-controlled while loop is used primarily for the number of data and strings that have been accurately known to be entered. Example

1. 1 #!/bin/sh
2. 2 Int=1
3. 3 while (($int <=5))
4. 4 Do
5. 5 echo $int
6. 6 Let "int++"
7. 7 Done

2, end tag control while loop is mainly used to not know the number of read data, but you can set a special data value to end the loop, the special value is called the end tag, by prompting the user input to operate. Example

2. 1 #用脚本演示使用结束标记控制while循环实现猜1 the number in the ~
4. 2 #!/bin/sh
6. 3
8. 4 echo "Please input the num (1~~10):"
10. 5 Read num
12. 6 while [[$num! = 4]]
14. 7 do
16. 8 If [$num-lt 4]
18. 9 Then
20. echo "Too small, Try again ..."
22. Read num
24. elif [$num-GT 4]
26. Then
28. echo "Too big, Try again ..."
30. Read num
32. + Else
34. Exit 0
36. Fi
38. Done
40. echo "Yes, you is right!"

3, Peugeot control while loop user input flag value to control the Loop end example

2. 1 #!/bin/sh
4. 2 echo "Please input the num:"
6. 3 Read num
8. 4 sum=0
10. 5 I=1
12. 6 signal=0
14. 7 while [[$signal! = 1]]
16. 8 Do
18. 9 If [$i-eq $num]
20. Ten Then
22. One-let "signal=1"
24. "Sum+=i"
26. echo "1+2 、、、 + $num = $sum"
28. + Else
30. "Sum=sum+i"
32. "I++"
34. + fi
36. Done

4. Example of a while loop with command-line control

1. 1 #!/bin/sh
2. 2
3. 3 echo "Please input arguements is $#"
4. 4 echo "What do you input:"
5. 5 while [[$*! =] "]
6. 6 do
7. 7 echo $
8. 8 shift
9. 9 Done

While loop "Go" in the shell