aria2 is a lightweight multi-protocol & multi-source command-line download utility. It supports HTTP/HTTPS, FTP, BitTorrent and Metalink. aria2 can be manipulated via built-in JSON-RPC and XML-RPC interfaces.

Aria2 1.18.3 release note,

This release fixes the bug which may cause assertion failure after multi-file downloads (e.g., multi-file metalink or torrent) are performed several times due to the bad handling of –bt-max-open-files option.

Changes

– Fix crash if unpause failed before assigning BtProgressInfoFile object

– Enable and check PIE in makerelease-osx

– Fix bug that numOpenFile_ is not reduced when MultiDiskAdaptor is deleted

– This bug caused assertion error in RequestGroupMan::ensureMaxOpenFileLimit

Installing Aria2 :

Ubuntu/Mint/Debian/Elementary OS/ Pear OS

$ sudo apt-get install aria2

Fedora/CentOS/

$ sudo yum install aria2

Arch/Manjaro

$ sudo pacman -Sy aria2

NB: Installing aria2 with the above method sometimes doesn’t provide you with the latest version.

You can download tarball and compile from source.

Using aria2

Downloading from WEB:

$ aria2c http://example.org/mylinux.iso

Downloading from 2 sources:

$ aria2c http://a/f.iso ftp://b/f.iso

Download using 2 connections per host:

$ aria2c -x2 http://a/f.iso

BitTorrent:

$ aria2c http://example.org/mylinux.torrent

BitTorrent Magnet URI:

$ aria2c 'magnet:?xt=urn:btih:248D0A1CD08284299DE78D5C1ED359BB46717D8C'

Metalink:

$ aria2c http://example.org/mylinux.metalink

Downloading URIs found in text file:

$ aria2c -i uris.txt

Enjoy.