Someone

                cksum=`cksum $i`

                if [ $sumexists -eq 0 ]
                then
                        echo "sum does not exist"
                        `cksum $i >> $1`
                        backfile=1
                else
                        echo "sum exists"
                        t=`grep -e "$cksum" $1`
                        if [ "$t" != "" ]
                        then
                                backfile=0
                        else
                                backfile=1
                        fi
                fi