注意：因子由下式给出：9！= 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1

这是我的代码：

#!/bin/bash
 
echo "Insert an Integer"
 
read input
 
if ! [[ "$input" =~ ^[0-9]+$ ]] ; then
   exec >&2; echo "Error: You didn't enter an integer"; exit 1
fi
 
function factorial
{
while [ "$input" != 1 ];
do
    result=$(($result * $input))
    input=$(($input-1))
done
}
factorial
echo "The Factorial of " $input "is" $result

它不断给我不同的乘法技术的错误：/

目前的输出是：

joaomartinsrei@joaomartinsrei ~/Área de Trabalho/Shell $ ./factorial.sh
Insert an Integer
3
./factorial.sh: line 15: * 3: Syntax error: operand expected (error token is "* 3")
The factorial of 3 is

非常感谢，
最好的祝福