shell脚本之计算n的阶乘

#!/bin/bash  while true do     read -p "please input a number to compute jiecheng: " number     (($number+0)) >/dev/null     if (($? != 0))     then         echo "input error,please input again!"         continue      fi     if (($number <= 0))     then         echo "input number must bigger than 0!please input again!"         continue      fi     sum=1      for i in `seq 1 $number`      do         sum=$((sum*i))     done     echo "${number}! = $sum"  done

文章来源: shell脚本之计算n的阶乘