X-Unikey is a tool that lets you type Vietnamese in an X Window environment. It has been tested with many popular programs such as OpenOffice, emacs, vim, QT, and GTK applications. It has all the features of Unikey, the Windows version, except that its GUI is simplified. All options are set through configuration file or keyboard shortcuts.
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.