循环输出,两个小程序

#!/bin/bash
a=1
while [ $a -le 5 ]
do
b=1
    while [ $b -le $a ]
    do
        echo -n $b
        let b++
    done
    let a++
    echo
done

-----------------------------------------------------------

results:

1

12

123

1234

12345
==================================

#!/bin/bash
a=1
c=1
while [ $a -le 9 ]
do
b=$[ $a-$c+1 ]
    while [ $b -le $a ]
    do
        echo -n $b
        let b++
    done
    let a=a+2
    let c++
    echo
done

------------------------------------------------------------

#!/bin/bash
for i in `seq 5`
do
   let j=$i;
   for k in `seq $i`
       do
           echo -n $j;
           let j++;
       done
  echo -e "\n"
done

------------------------------------------------------------

results:

1

23

345

4567

56789

==================================