what is FTP Loopback in unix?

I am writing a shell script where I need to automate FTP loopback. I am not aware of what FTP loopback is and how I can automate to send many files? Here is what I have been given in a document?

ftp loopback username: xxxx Password : xxxxx ftp> cd /tmp for n files in /tmp put file1 put file2 etc. bye