shell编程---while简单例程

              初学shell编程，写了个简单的程序。

#! /bin/sh
#打印10以内的加法表
i=1
while [ $i -le 9 ]
    do
       row=1
       colume=$i
       while [ $row -le $i ]
          do
            if((i==9))
             then
               echo -n "$row+$colume=$((row+colume)) "
            else 
               echo -n "$row+$colume=$((row+colume))  "
            fi
            row=$(expr $row + 1)
            colume=$(expr $colume - 1)
          done
       echo
       ((i=$i+1))
done