shell脚本流程控制格式示例（while, until与for）

用shell脚本制作等腰直角三角形

[root@CO01 ~]# bash ff.sh 
 * 
 *  * 
 *  *  * 
 *  *  *  * 
 *  *  *  *  * 
 *  *  *  *  *  * 
 *  *  *  *  *  *  * 
 *  *  *  *  *  *  *  * 
 *  *  *  *  *  *  *  *  * 
 *  *  *  *  *  *  *  *  *  * 
[root@CO01 ~]# cat ff.sh 
#!/bin/bash
whileSJ()
{
        a=1
        b=10
        c=1
        while [ $a -le $b ]
        do
                c=1
                for i in `seq $c $a`
                do
                        printf " * "
                        let c=$c+1
                done
                printf "\n"
                let a=$a+1
        done
}
whileSJ
[root@CO01 ~]# 

同样的形状除了用while也可用以下两种方式表示：
1.until

untilSJ()
{
        a=1
        b=10
        until [ $a -ge $b ]
        do
                c=1
                while [ $c -le $a ]
                do
                        printf " * "
                        let c=$c+1
                done
                printf "\n"
                let a=$a+1
        done
}

untilSJ

2.for

forSJ()
{
        a=10
        b=1
        c=1
        i=1
        for num in `seq $b $a`
        do
                c=1
                while [ $c -le $num ]
                do
                        printf " * "
                        let c=$c+1
                done
                printf "\n"
        done

}
forSJ