Bash-For循环不适用于声明中的变量

Question

for i in {0..3}
do
   echo $i
done

返回

0
1
2
3

但是

firstNumber=$1
lastNumber=$2

for i in {$firstNumber..$lastNumber}
do
   echo $i
done

例如，

返回

{0..3}

如何在For循环声明中使用变量？

Answer 1

for ((i=$firstNumber; i <= $lastNumber; i++)); do echo $i; done