uGet is an GTK+3 Open Source app for GNU/Linux.
uGet is also a portable app for Windows (XP+).
I am use Ubuntu 12.04 LTS.
1. Open terminal Ubuntu and copy-paste this command.
sudo apt-get install uget
2. After have done, open Mozilla Firefox to integration with uGet.
Click tools ==> Add-Ons ==> Search Flashgot Mass Downloader
Or you can to follow this link to install Flashgot https://addons.mozilla.org/en-US/firefox/addon/flashgot/?src=userprofile
3. On Flashgot click Preferences ==> General ==> Download Manager ==> Choice uGet and click Ok.
4. uGet for Download
You can setting uGet appropriate your wish.
To read more describe of uGet you can visit this link http://ugetdm.com/