$ tail -f multtable.txt
0
9
18
27
36
45
54
63
72
81


##</code><code>##

for ix in 0 1 2 3 4 5 6 7 8 9 
do
   for iy in 0 1 2 3 4 5 6 7 8 9 
   do
         n=`expr ${ix} '*' ${iy}`
         echo $n >> multtable.txt
   done 
done