File Transfer Protocol or FTP is a simple and popular method for copying files over the Internet. FTP is the UNIX user interface to the Internet protocol and enables you to download or transfer files to your computer from another computer network host if its System Administrator has made the privilege available. You can download files, documents, programs, and other archived data even when you and your FTP host use different operating systems.

Computers throughout the world store files containing a great deal of useful information. Some FTP hosts or networks restrict access to these files but many hosts provide a general purpose account (called Anonymous FTP) where you can have unlimited access to files.

FTP is the original tool used for transferring files on the Internet. The World Wide Web and Gopher also allow you to obtain some files and although more and more files are being made available via WWW, some files are only available via FTP. So it is important that you are aware of the FTP procedure.

Anonymous Login

In order to access files on a host computer, you must have an account and login name. Most users transfer files using FTP by logging in using the name anonymous. For this reason, FTP is often referred to as anonymous FTP.

To access an anonymous FTP site, you first run your FTP software (you can download one at a number of sites such as Tucows and Nonags). Then you get to an ftp> prompt. Some systems make this prompt available through a menu while others require you to type ftp at the system prompt. You could always check the tech support people at your ISP to ask for the exact procedure for reaching FTP.

At the ftp> prompt, type open <name of host>. If you want to access a document at the host named sunsit.unc.edu, for example, you type

ftp> open sunsit.unc.edu

Let's assume that the remote host is up and running and you typed the name correctly, you will be connected and asked for a user login name and password. Type anonymous at the login request and type your complete internet address when you are asked for the password.

If you're lucky and your connection goes through (some hosts put limits on the number of off-site FTP users at any given time), you're logged in, given a guest account with restrictions, shown the time, and returned to the ftp> prompt. The prompt means that the system is waiting for you to enter one of the FTP commands.

FTP Commands

Here are some of the more basic FTP commands that work on remote UNIX systems:

help	Lists the available commands.
help <command>	Describes the effect of the command.
?	Lists the FTP commands supported.
ls	Lists contents of the active directory.
ascii	Changes the transfer mode to transfer a text file.
binary	Changes the transfer mode to transfer a binary file.
cd <directory name>	Enables the user to change directories, moving down the directory tree hierarchy.
cd ..	Enables the user to return to the previous directory, moving up the directory tree hierarchy.
get <filename>	Enables the user to get a file from the remote computer and copy it to the local system.
mget <filename/wildcard>	Enables the user to get multiple files from the remote computer and copy them to the local system; uses the * wildcard to replace repeated characters. To get all files beginning with the capital letter P, for example, type mget P*
put <filename>	Enables the user to transfer a file from the local system to the remote system, if permission is granted on the remote site.
mput <filename/wildcard>	Enables the user to transfer multiple files from the local system to the remote system, if permission is granted on the remote site; uses the * wildcard to replace repeated characters. To transfer all files ending with the file extension txt, for example, type mput *.txt.
pwd	Displays the name of the working directory to which you are currently connected.
bye	Logs the user off the remote system.
quit	Also logs the user off the remote system.

FTP Etiquette

Remember that accessing an FTP connection on a remote site is a privilege that shouldn't be abused. The system was established for the purpose of doing research, development, and other work.

When you FTP to a site, you are a guest at that site. The files you may access have been made publicly available on a voluntary basis by the "owner" of that site.

When you login, you are in fact using space on the host's computer. Since we don't want to interfere with the normal daily work at the sponsoring organization of an FTP site, it is best to limit your FTP activities to the hours before 8 AM and after 5 PM THEIR local time. Keep your sessions short and after normal business hours. It may be during weekends, or late at night.

When you download, check for copyright or licensing agreements. It is the responsibility of the person downloading to pay any authors registrations fee if there is one.

Also, out of politeness, use your email address as your password if you log in as anonymous. It will give the owners of the FTP site a way to see who accesses their files, and serves as sort of a guest book.

File Formats

FTP files can be in either ASCII or Binary format. When you transfer FTP files, you must set the transfer format to one or the other. ASCII files must be transferred using ASCII mode, binary files must be transferred using binary mode. If you transfer ASCII files with binary mode (or vice versa) you will be unable to read or use the file you get.

How do you know which mode to use? ASCII files are text only files. Binary files are non- text files and include software files, image files, sound files and compressed files. The usual default transfer type at an FTP site is ASCII. If you know you will be downloading binary files, type "binary" (without quotations) prior to giving the "get" command.

Often, the extension indicates the type of file, as .txt or .doc indicate text or document files. The other reason files have these extensions is to inform users if they have been compressed (made smaller for the sake of storage) and what program was used to compress them. This is important because to use these files you must decompress them using the same program as the one that compressed them.

Some common extensions you might see and what they mean are:

.bin	MacBinary encoded files
.com	Executable file; no decompression
.Doc or .doc	Usually a text file;no decompression needed
.exe	Executable file; no decompression
.gif	Graphics file; need gif viewer to use
.gz	UNIX version of zip, use gunzip
.Hqx or .hqx	Use Mac Program,"StuffIt Expander" to uncompress
.jpg	need JPEG viewer
.PS or .ps	PostScript document, no decompression needed
.SEA or .sea	Mac format, no decompression needed
.Shar or .shar	UNIX, use unshar to decompress
.sit	Mac StuffIt compressed files
.tar	Use UNIX program "Tar"to decompress
.tif	Graphics file; Need tif viewer to use
.Txt or .txt	Text file; no decompression needed.
.uu	UU encoded files
.wp	Word perfect file; no decompression needed
.wpg	Graphics file; Need wpg viewer to use
.Z or .z	Use UNIX program "Uncompress"
.Zip or .zip	Use Dos program "Unzip" to decompress
.ZOO or .zoo	UNIX and DOS, use zoo to decompress

Where are the FTP Sites?

There are many sources of addresses for FTP sites. Many newsgroups are rich sources of information regarding FTP locations. The groups news.announce.newusers, comp.archives, news.list, alt.best.of.internet, comp.internet.library, and alt.internet.services are just a few that regularly provide listings of locations.

Here are some popular FTP sites:

sumex-aim.stanford.edusunsit.unc.edu	Has an abundance of information as well as files from other sites.
wuarchive.wustl.edu	When you're looking for documents, lyrics, and software.
oak.oakland.edu	Macintosh, Amiga, Apple 2, Apollo.
ftp.sura.net	This is a huge site of PC and UNIX archives.
nic.merit.edu	Contains documents on new user information.
ftp.cni.org	If you want information about the Internet Hunt

Some FTP Tips

• Since text files are usually not compressed they can be transferred using ASCII. However, all compressed files must be transferred using binary mode.