Shell 编写倒着的*三角形

#!/bin/bash
read -p "Input line number: " line
for ((i=0; i<$line; i++))
do
        for ((k=$i; k>0; k--))
        do
            echo -n " "
        done
        for ((h=$((2*($line-$i)-1)); h>0; h--))
        do
            echo -n "*"
        done
        echo
done