#!/bin/bash

i=1
while (( "$i" <= 9 ))
do
        j=1
        while (( "$j" <= "$i" ))
        do
                echo -n "*"            #-n表示不换行显示
                let j++
        done
        echo ""                            #表示换行
        let i++
done


[root@server100 shell]# ./loop3.sh
*
**
***
****
*****
******
*******
********
*********