lftp is a sophisticated command line based file transfer program. Supported protocols include FTP, HTTP, SFTP, and FISH. It has a multithreaded design allowing you to issue and execute multiple commands simultaneously or in the background. It also features mirroring capabilities and will reconnect and continue transfers in the event of a disconnection. Also, if you quit the program while transfers are still in progress, it will switch to nohup mode and finish the transfers in the background. Additional protocols supported: FTP over HTTP proxy, HTTPS and FTP over SSL, BitTorrent protocol. IPv6 is fully supported. There are lots of tunable parameters, including rate limitation, number of connections limitation and more.
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 bandwidth to the maximum. It supports downloading a file from HTTP(S)/FTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP is uploaded to the BitTorrent swarm. Using Metalink's chunk checksums, aria2 automatically validates chunks of data while downloading a file like BitTorrent.