UNIX for Dummies Questions & Answers

sed -n "/Grid-ref/{N;s/\n.*$//;N;p}" file >newfile

sed -n "/^Grid-ref=/{N;p;}" file

awk ' { if ( $0 ~ /^Grid-ref/ ) {
        if( tot == 0 ) { tot = NR }
        else {
                tot = NR - tot -1;
                for( i = 1; i <= nf ; ++i )
                        printf("%.1f ", arr[i] / tot );
                printf("\n")
                for( i = 1; i <= nf ; ++i )
                        arr[i] = 0
                tot = NR;
        }
        print
}
else
        for( i = 1; i <= NF ; ++i )
                arr[i] = arr[i] + $i
nf=NF
}
END {
tot = NR - tot
for( i = 1; i <= nf ; ++i )
        printf("%.1f ", arr[i] / tot );
printf("\n")
}
' file