echo > quiz1.txt
a=1
A="dat/00$a.dat"
while test $a -ne 9
do
   b=2
   B="dat/00$b.dat"
   while test $b -ne 9 
   do
     if [ `diff $A $B | wc -c` -eq 0 ]
     then if [ $a -lt $b ] 
        then echo "00$a.dat 00$b.dat" >> quiz1.txt
          fi
     fi
     b=`expr $b + 1`
   done
#
   c=10
   C="dat/0$c.dat"
   while test $c -ne 99
   do
     if [ `diff $A $C | wc -c` -eq 0 ]
     then if [ $a -lt $c ]
        then echo "00$a.dat 0$c.dat" >> quiz1.txt
          fi
     fi
     c=`expr $c + 1`
   done
#
   if [ `diff $A dat/100.dat | wc -c` -eq 0 ]
   then echo "00$a.dat 100.dat" >> quiz1.txt
   fi
#
   a=`expr $a + 1`
done
#
#
d=10
D="dat/0$d.dat"
while test $d -ne 99
do
#
   c=10
   C="dat/0$c.dat"
   while test $c -ne 99
   do
     if [ `diff $D $C | wc -c` -eq 0 ]
     then if [ $d -lt $c ]
        then echo "0$d.dat 0$c.dat" >> quiz1.txt
          fi
     fi
     c=`expr $c + 1`
   done
#
   if [ `diff $D dat/100.dat | wc -c` -eq 0 ]
   then echo "0$D.dat 100.dat" >> quiz1.txt
   fi
#
   d=`expr $d + 1`
done