while do done用法
"while do done" is a common loop construct used in bash scripting. It is used to repeatedly execute a set of commands as long as a specific condition is true.
The syntax of the "while do done" loop is as follows:
```
while condition
do
  commands
done
```
Here is how it works:
1. The `condition` is checked at the beginning of each iteration.
2. If the `condition` is true, the `commands` inside the loop are executed.
3. After the execution of the commands, the program jumps back to the beginning of the loop to check the `condition` again.
construct用法4. This process continues until the `condition` becomes false. Once the `condition` is false, the loop exits and the program continues with the next statement after the "done" keyword.
Here is an example to demonstrate the usage of "while do done":
```
count=1
while [ $count -le 5 ]
do
  echo "Count: $count"
  count=$((count+1))
done
```
This script will output the numbers from 1 to 5 by incrementing the `count` variable in each iteration. The loop will continue until `count` becomes 6, and then it will exit.

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