sort very large file

LC_ALL=C sort -u --buffer-size=2G --temporary-directory=/root/Desktop/tmp --output=joined_sorted.txt joined.txt 
uniq joined_sorted.txt joined_sorted_uniqed.txt
split bigFileName -l 按行分割
wc -l joined.txt 
split -l 10000000 joined.txt joined_split_
for f in joined_split_*; do
  sort -u "$f" > "$f"_sorted
done
sort -u -m joined_split_*_sorted > final.out