aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, BitTorrent, and Metalink. It has a powerful segmented downloading ability, downloading a file from multiple sources and multiple protocols and utilizing your download

aria2 - CLI Metalink/BitTorrent client source code

aria2的东东，下载的，我也不知道是什么东东(I don't konw what it is . you can download it if you inster)