aria2 can download a file from multiple sources/protocols and tries to utilize your maximum download bandwidth. 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.
There are other alternative applications. But aria2 has 2 distinctive features:
(1) aria2 can download a file from several URIs(HTTP(S)/FTP/BitTorrent)
(2) If you give aria2 a list of URIs, aria2 downloads them concurrently.
You don't have to wait for the current download queue to finish one file at a time anymore. aria2 tries to utilize your maximum download bandwidth and downloads files quickly.
Installation: aria2 binary packages are now available on the variety of platforms.
Debian & Ubuntu: apt-get install aria2
Fedora: yum install aria2
OpenSuse 11.1: "1-click" installer for aria2
Mandriva: urpmi aria2
aria2 uses 5 connections to download 1 file by default. To limit the number of connections to, say, just 1, use -s1 option.
Note: To pause a download, press Ctrl-C. You can resume the transfer by running aria2c with the same arguments at the same directory. You can change URIs as long as they are pointing to the same file.
Download a file:
Download a file using 2 connections:
aria2c -s2 http://host/image.iso http://mirror1/image.iso http://mirror2/image.iso
Download a file from HTTP and FTP servers:
aria2c http://host1/file.zip ftp://host2/file.zip