Enhanced

Although pretty much outdated, the File Transfer Protocol (FTP) still plays a significant role. For 20 years, LFTP has offered a greatly expanded command set for the command line that handles secure transmissions, without being excessively difficult to handle.

FTP dates back to 1985. Designed for transferring files between two computers, FTP is a relic from the infancy of modern IT. Today it has lost much of its former importance, not least because of some serious security problems: It neither encrypts the FTP username and password, nor protects the data against manipulation during transfer.

FTP via SSL (FTPS) or SSH (SFTP) counteracts these weaknesses. The two methods are considered to be equally secure, and they encrypt both data and metadata during transmission. In most cases, SFTP proves to be more flexible and much simpler in practice.

Alternatives

FTP alternatives have been around for a long time – on Linux, the venerable secure copy (scp) has been used to transfer data to other machines from the command line. In the meantime, WebDAV (Web Distributed Authoring and Versioning), a kind of extension of HTTP with new commands, has also developed into a useful replacement.

Nevertheless, FTP is a marathon runner for various reasons, most often because many web hosts only offer FTP and leave WebDAV or SSH out of the equation. FTP is thus likely to be around for a while.

LFTP is a very powerful extension of the original FTP command set that has been under development since 1997. It is developed by Alexander Lukyanov, is licensed under the GNU Public License (GPL), and was last updated to version 4.8.0 in July 2017 [1]. LFTP supports a wide range of protocols, including plain vanilla FTP, along with FTPS, SFTP, HTTP, HTTPS, HFTP, FXP (see the "FXP" box), Fish, and BitTorrent.

Special Features

LFTP stands out from most other command-line FTP clients with advanced features such as recursive mirroring and the ability to update entire directory trees and manage bookmarks. Several simultaneous sessions to different servers are implemented by assigning commands to slots in a separate shell. Additionally, scheduled transfers can be queued and scheduled, and bandwidth use can be managed. If a transmission breaks down, LFTP resumes it later on at the same location. If you exit LFTP, it continues to process the active tasks in the background.

Client-Server Model

LFTP can be found in the repositories of most distributions; thus, you can usually install it with the package manager.

To test LFTP without an active server, it is best to install an FTP server on a second local machine, to which LFTP then establishes a connection. For example, the very secure FTP daemon (vsftpd) [2] is a good way to go, because it does not require any configuration for simple tests. Before you can start, all you have to do is remove the # comment sign in front of the #write_enable=YES line in /etc/vsftpd.conf.

Last but not least, create a directory on the client computer for the test and fill it with some data.