LFTP is a sophisticated file transfer program with command line interface. It supports FTP, HTTP, FISH, SFTP, HTTPS and FTPS protocols. GNU Readline library is used for input.
Every operation in lftp is reliable, that is any non-fatal error is handled and the operation is retried automatically. So if downloading breaks, it will be restarted from the point automatically. Even if ftp server does not support REST command, lftp will try to retrieve the file from the very beginning until the file is transferred completely. This is useful for dynamic-ip machines which change their IP addresses quite often, and for sites with very bad internet connectivity.
If you exit lftp when some jobs are not finished yet, lftp will move itself to nohup mode in background. The same happens when you have a real modem hangup or when you close an xterm.