FTP is a file transfer protocol for exchanging files over any TCP/IP based network to manipulate files on another computer on that network regardless of which operating systems are involved (if the computers permit FTP access). There are many existing FTP client and server programs. FTP servers can be set up anywhere between game servers, voice servers, internet hosts, and other physical servers.
GUI FTP Clients
gFTP is a free/open source multithreaded FTP client. It is most used on Unix-like systems, but it can be also be used on Mac OS X. It includes both a GUI (which utilizes the GTK+) and a command-line interface.
Install gftp in Ubuntu
sudo aptitude install gftp