du -b . |awk '{sub(/-[0-9]+/,"",$2);sum[$2]+=$1;} END{for(k in sum){print sum[k],k;}}' |sort -n |numfmt --to=iec-i --suffix=B --padding=7
without numfmt
du -b . |awk '{sub(/-[0-9]+/,"",$2);sum[$2]+=$1;} END{for(k in sum){print sum[k],k;}}' |sort -n |awk '{print $1/1024/1024/1024 "G", $2}'