lftp is a command-line

Command-line interface

A command-line interface is a mechanism for interacting with a computer operating system or software by typing commands to perform specific tasks...

 file transfer program (FTP client) for UNIX

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 and Unix-like systems. It was written by Alexander Lukyanov, and is made available under the GNU General Public License

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

.

Besides FTP

File Transfer Protocol

File Transfer Protocol is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server...

, it also supports FTPS

FTPS

FTPS is an extension to the commonly used File Transfer Protocol that adds support for the Transport Layer Security and the Secure Sockets Layer cryptographic protocols....

, HTTP, HTTPS

Https

Hypertext Transfer Protocol Secure is a combination of the Hypertext Transfer Protocol with SSL/TLS protocol to provide encrypted communication and secure identification of a network web server...

, HFTP

HFTP

HFTP is a protocol for accessing FTP resources via HTTP proxy. It uses ftp URL scheme in HTTP requests to a proxy.The notation of HFTP was introduced in Lftp client to distinguish between plain FTP protocol and indirect access via HTTP proxy. Lftp supports hftp URL scheme to select HFTP protocol...

, FISH

Files transferrer over shell protocol

Files transferred over Shell protocol is a network protocol that uses Secure Shell or Remote Shell to transfer files between computers and manage remote files....

, and SFTP

SSH file transfer protocol

In computing, the SSH File Transfer Protocol is a network protocol that provides file access, file transfer, and file management functionality over any reliable data stream...

 by specifying the desired protocol in a location URL

Uniform Resource Locator

In computing, a uniform resource locator or universal resource locator is a specific character string that constitutes a reference to an Internet resource....

. One feature which is especially handy is support for FXP

File eXchange Protocol

File eXchange Protocol and is a method of data transfer which uses FTP to transfer data from one remote server to another without routing this data through the client's connection. Conventional FTP involves a single server and a single client; all data transmission is done between these two...

 i.e. data transfers between two FTP servers, bypassing the client machine.