Chapter 5

FILE TRANSFER PROTOCOL (ftp)


This is a very important service available on the Internet. The file transfer protocol (ftp) gives you the ability to retrieve and store files to and from a distant computer. Many computers on the Internet allow login with the username "anonymous" and your E-mail address as the password. While nowadays, the availability of "gopher" or the World Wide Web (Lynx and graphical WEB) make this somewhat redundant, it is good to know how file transfer happens, even if in your application it occurs in the background and is not directly visible to you. There are a large number of files still stored on ftp sites.

Hundreds of systems connected to the Internet have file libraries and archives accessible to the public. Much of this consists of free or low-cost shareware programs for virtually every make of computer. For example, if you want a different communications program for your IBM, or feel like playing a new game on your Amiga, you'll be able to get it from the Net, with ftp.

There are libraries of documents as well. If you want a copy of a recent U.S. Supreme Court decision, you can find it on the Net. Copies of historical documents, from the Magna Carta to the Declaration of Independence, are yours for the asking, along with a translation of a telegram from Lenin ordering the execution of rebellious peasants. You can find song lyrics, poems, even text summaries of every "Lost in Space" episode ever made. You can find extensive files detailing everything you could ever possibly want to know about the Net itself.

First you'll see how to get these files, then we'll show you where they are kept.

5.1 Using ftp

Starting ftp is easy. Fig.5-1 shows the first step, which is to go to the First Menu and select item 2, FTP. This opens the application program called FTP on the VSNL computer, and gives you the " ftp> " prompt.

Fig.5-1 Opening FTP

VIDESH SANCHAR NIGAM LIMITED
WELCOME TO VSNL INTERNET ACCESS SERVICE

UNAUTHORIZED ACCESS PROHIBITED
-------------------------------

Select options by no. :

H. Help - List of commands on UNIX Prompt
0. Logout - Logout of the system

1. E-mail - Electronic mail service
2. FTP - File Transfer service
3. Telnet - Log on to another system
4. Lynx - World Wide Web browser (WWW)
5. Chat - Internet Relay Chat (IRC)
6. Kermit - Transfer files to your PC
7. New Password - Change your password
8. Zmodem download - Download files thru ZModem
9. Zmodem upload - Upload files thru Zmodem
10. UNIX Prompt - Exit to UNIX prompt

Your Selection :2


At the "ftp>" prompt, type "open site.name", as indicated below,

ftp> open site.name

and press <enter>, where "site.name" is the address of the ftp site where you hope to get the file you want.

One major difference between telnet and ftp is that it is considered bad form to connect to most ftp sites during their business hours (generally 6 a.m. to 6 p.m. local time). This is because transferring files across the network blocks up considerable communication resources, which during the day is likely to be needed for whatever the computer's main function is. There are some ftp sites that are accessible to the public 24 hours a day.

The first question is how to locate your desired information or file on the multitude of Internet sites or host computers. There are three approaches to the answer:

5.2 Browsing an anonymous ftp site

Supposing you know the site where the file you want is stored, what is the procedure to get the file? This question is answered by showing you a transcript of an ftp session, step by step. Let us assume you have found out that your desired file may be on the sites "ftp.cica.indiana.edu" or "oak.oakland.edu". Thus at the ftp> prompt, you should enter the first address.

Fig.5-2 shows your entry at the ftp prompt, and following that, the responses received from the ftp site, and your further entries at subsequent ftp> prompts:

Fig.5-2 Response from an ftp site

ftp> open ftp.cica.indiana.edu
Connected to cica.cica.indiana.edu.

220-** ** I M P O R T A N T R E A D T H I S P L E A S E **
220-** 220-** The Center for Innovative Computer Applications
no longer houses

220-** the Windows ftp archive. It has moved to
ftp.winsite.com,
220-** 199.26.178.13. Mail winsite@winsite.com for more information or
220-** questions.
220-** 220-** All cica research files are accessible via
ftp.cica.indiana.edu
220-** [129.79.20.27].
....... (Some information given by the site)
220-

220 cica FTP server (Version wu-2.4(2) Fri Dec 29 14:01:51 EST 1995) ready.
Name (ftp.cica.indiana.edu:rajm): anonymous
530-Sorry! We have reached maximum number of connections (50).
530-You may try again later, or reach our site via:
530-gopher:
gopher.cica.indiana.edu
530-WWW:
www.cica.indiana.edu
530 User anonymous access denied.
Login failed.
421 Service not available, remote server has closed connection
[ Please note t

ftp> open ftp.cica.indiana.edu
Connected to cica.cica.indiana.edu.

220-** ** I M P O R T A N T R E A D T H I S P L E A S E **
220-** 220-** The Center for Innovative Computer Applications
no longer houses

220-** the Windows ftp archive. It has moved to
ftp.winsite.com,
220-** 199.26.178.13. Mail winsite@winsite.com for more information or
220-** questions.
220-** 220-** All cica research files are accessible via
ftp.cica.indiana.edu
220-** [129.79.20.27].
....... (Some information given by the site)
220-

220 cica FTP server (Version wu-2.4(2) Fri Dec 29 14:01:51 EST 1995) ready.
Name (ftp.cica.indiana.edu:rajm): anonymous
530-Sorry! We have reached maximum number of connections (50).
530-You may try again later, or reach our site via:
530-gopher:
gopher.cica.indiana.edu
530-WWW:
www.cica.indiana.edu
530 User anonymous access denied.
Login failed.
421 Service not available, remote server has closed connection
[ Please note that a site may be very busy and you may not be
able to get in, as it happened at the site above. So you t

ftp> open ftp.cica.indiana.edu
Connected to cica.cica.indiana.edu.

220-** ** I M P O R T A N T R E A D T H I S P L E A S E **
220-** 220-** The Center for Innovative Computer Applications
no longer houses

220-** the Windows ftp archive. It has moved to
ftp.winsite.com,
220-** 199.26.178.13. Mail winsite@winsite.com for more information or
220-** questions.
220-** 220-** All cica research files are accessible via
ftp.cica.indiana.edu
220-** [129.79.20.27].
....... (Some information given by the site)
220-

220 cica FTP server (Version wu-2.4(2) Fri Dec 29 14:01:51 EST 1995) ready.
Name (ftp.cica.indiana.edu:rajm): anonymous
530-Sorry! We have reached maximum number of connections (50).
530-You may try again later, or reach our site via:
530-gopher:
gopher.cica.indiana.edu
530-WWW:
www.cica.indiana.edu
530 User anonymous access denied.
Login failed.
421 Service not available, remote server has closed connection
[ Please note t

ftp> open ftp.cica.indiana.edu
Connected to cica.cica.indiana.edu.

220-** ** I M P O R T A N T R E A D T H I S P L E A S E **
220-** 220-** The Center for Innovative Computer Applications
no longer houses

220-** the Windows ftp archive. It has moved to
ftp.winsite.com,
220-** 199.26.178.13. Mail winsite@winsite.com for more information or
220-** questions.
220-** 220-** All cica research files are accessible via
ftp.cica.indiana.edu
220-** [129.79.20.27].
....... (Some information given by the site)
220-

220 cica FTP server (Version wu-2.4(2) Fri Dec 29 14:01:51 EST 1995) ready.
Name (ftp.cica.indiana.edu:rajm): anonymous
530-Sorry! We have reached maximum number of connections (50).
530-You may try again later, or reach our site via:
530-gopher:
gopher.cica.indiana.edu
530-WWW:
www.cica.indiana.edu
530 User anonymous access denied.
Login failed.
421 Service not available, remote server has closed connection
[ Please note that a site may be very busy and you may not be
able to get in, as it happened at the site above. So you try
another site. ]

ftp> open oak.oakland.edu
Connected to oak.oakland.edu.
220 oak.oakland.edu FTP server (Version wu-2.4(9) Wed May 3
15:02:49 EDT
1995) ready.

Name (oak.oakland.edu:rajm): anonymous
331 Guest login ok, send your complete e-mail address as
password.

ftp> open oak.oakland.edu
Connected to oak.oakland.edu.
220 oak.oakland.edu FTP server (Version wu-2.4(9) Wed May 3
15:02:49 EDT
1995) ready.

Name (oak.oakland.edu:rajm): anonymous
331 Guest login ok, send your complete e-mail address as


You may find useful information on this site. Therefore, you decide to log on to the site. Fig.5-3 shows information and instructions which are given by the site after you have logged on.

Fig.5-3 Information from an ftp site you have logged on to.

230-
230- Welcome to
230- THE OAK SOFTWARE REPOSITORY
230- A service of Oakland University, Rochester Michigan
230-
230- If you have trouble using OAK with your ftp client, please try using
230- a dash (-) as the first character of your password -- this will turn
230- off the continuation messages that may be confusing your ftp client.
230- OAK is a Unix machine, and filenames are case sensitive.
230-
230- Access is allowed at any time. If you have any unusual problems,
230- please report them via electronic mail to
archives@Oakland.Edu
230-
230- Oak is also on the World Wide Web, URL:
http://www.acs.oakland.edu/oak/
230-
230- To search for files, use the command: quote site exec index filename
230-
230-Please read the file README
230- it was last modified on Fri Mar 22 15:07:51 1996 - 23 days ago
230 Guest login ok, access restrictions apply.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> dir
[ A command like the DOS's dir is issued to see the contents of
the present directory. ]
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
total 2042
-rw-r--r-- 1 w8sdz OAK 0 Nov 13 1994 .notar
drwxr-x--- 2 root operator 8192 Dec 31 1994 .quotas
drwx------ 2 root system 8192 Dec 30 1994 .tags
-rw-r--r-- 1 jeff OAK 1917789 Apr 13 03:20 Index-byname
-r--r--r-- 1 w8sdz OAK 1386 Mar 22 15:07 README
drwxr-xr-x 3 jeff OAK 8192 Mar 15 15:39 SimTel
d--x--x--x 3 root system 8192 Jan 19 1995 bin
d--x--x--x 2 root system 8192 Jun 12 1995 core
drwxr-x--- 3 cpm OAK 8192 Mar 22 16:46 cpm-incoming
d--x--x--x 5 root system 8192 Sep 12 1995 etc
drwxrwx--- 2 incoming OAK 8192 Jun 21 1995 incoming
drwxrwx--- 2 nt OAK 8192 Jan 16 22:26 nt-incoming
drwxr-xr-x 3 w8sdz OAK 8192 Apr 5 10:11 pub
drwxr-xr-x 17 w8sdz OAK 8192 Apr 9 09:51 pub2
drwxr-xr-x 9 w8sdz OAK 8192 Apr 5 10:04 pub3
drwxr-xr-x 5 jeff system 8192 Mar 15 16:05 pub4
drwxr-xr-x 5 w8sdz system 8192 Apr 9 09:50 pub5
drwxr-xr-x 3 jeff OAK 8192 Mar 15 15:39 simtel
drwxr-xr-x 2 jeff OAK 8192 Apr 17 1994 siteinfo
drwx------ 45 w8sdz OAK 8192 Apr 12 03:21 w8sdz
226 Transfer complete.
ftp> cd simtel


Your entry at the last ftp> prompt, shown in Fig.5-3, was to go to the sub-directory named simtel, indicated in the third last line of the listing, above. This name is usually given to the directory which holds the shareware software. The ftp session transcript continues in Fig. 5-4.

Fig.5-4 Contents of the SimTel directory on the ftp site.

250-The files in this directory tree are a mirror of SimTel, the Coast to
250-Coast Software Repository (tm). Please read README.COPYRIGHT for
250-information on distribution rights.

250-
250-Please read the file README.COPYRIGHT
250- it was last modified on Sat Oct 21 11:51:00 1995 - 176
days ago

250-Please read the file README.MIRRORING
250- it was last modified on Sat Oct 21 11:50:00 1995 - 176
days ago

250 CWD command successful.
ftp> ls -l
[ "ls-l" is the UNIX command to get the directory listing of files. ]
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
total 57
-rw-r--r-- 2 jeff OAK 172 Oct 22 01:33 .message
-rw-r--r-- 2 jeff OAK 172 Oct 22 01:33 .msg -rw-r--r-- 1 jeff OAK 0 Jan 28 1995 .notar
-rw-r--r-- 1 jeff OAK 4934 Oct 21 11:51 README.COPYRIGHT
-rw-r--r-- 1 jeff OAK 1913 Oct 21 11:50 README.MIRRORING
drwxr-xr-x 226 jeff OAK 8192 Apr 13 23:46 msdos
drwxr-xr-x 29 jeff OAK 8192 Apr 13 23:35 nt
drwxr-xr-x 18 jeff OAK 8192 Apr 14 00:21 os2
drwxr-xr-x 9 jeff OAK 8192 Apr 13 11:52 vendors
drwxr-xr-x 94 jeff OAK 8192 Apr 13 23:52 win3
drwxr-xr-x 47 jeff system 8192 Apr 14 00:18 win95
226 Transfer complete.

Let's decipher this:

The ftp command for displaying a directory is either "ls - l" or "dir". It is advisable to keep in mind that only "ls - l" works on your own host system.

The very first letter on each line tells you whether the listing is for a directory or a file. If the first letter is a "d" or an "l", it's a directory. Otherwise, it's a file.

The rest of that weird set of letters and dashes consist of "flags" that tell the ftp site who can look at, change or delete the file. You can safely ignore it. You can also ignore the rest of the line until you get to the second number, the one just before the date. This tells you how large the file is, in bytes. If the line is for a directory or sub-directory, the number gives you a rough indication of how many items are in that directory -- a directory listing of 512 bytes is relatively small. Next comes the date the file or directory was uploaded, followed (finally!) by its name.

Notice the README. files up at the top of the directory. Most archive sites have a "read me" document, which usually contains some basic information about the site, its resources and how to use them. How to read a file at an ftp site will be discussed in detail later.

Let us assume you want the MS-DOS versions of the files. Therefore, you change to the msdos directory by typing "cd msdos" at the ftp prompt as shown below:

ftp> cd msdos

This takes you to the directory which holds msdos files and sub-directories, as shown in Fig.5-5.

Fig.5-5 Contents of msdos directory.

250-This MS-DOS collection is a mirror of SimTel, the Coast to Coast
250-Software Repository (tm). Questions about or comments on this
250-collection should be sent to service@SimTel.Coast.NET.
250-
250-Please read the file README.COPYRIGHT
250- it was last modified on Sun Dec 10 15:00:00 1995 - 126 days ago
250-Please read the file README.MIRRORING
250- it250-This MS-DOS collection is a mirror of SimTel, the Coast to Coast
250-Software Repository (tm). Questions about or comments on this
250-collection should be sent to service@SimTel.Coast.NET.
250-
250-Please read the file README.COPYRIGHT
250- it was last modified on Sun Dec 10 15:00:00 1995 - 126 days ago
250-Please read the file README.MIRRORING
250- it was last modified on Sun Dec 10 15:01:00 1995 - 126 days ago
250-Please read the file README.descriptions
250- it was last modified on Sun Dec 10 15:01:00 1995 - 126 days ago
250-Please read the file README.dir-list
250- it was last modified on Fri Mar 29 11:25:00 1996 - 16 days ago
250-Please read the file README.file-formats
250- it was last modified on Sun Dec 10 15:02:00 1995 - 126 days ago
250-Please read the file README.how-to-upload
250- it was last modified on Sun Mar 17 20:37:00 1996 - 28 days ago
250-Please read the file README.mirror-sites
250- it was last modified on Sun Mar 17 20:29:00 1996 - 28 days ago
250-Please read the file README.simtel-cdrom
250- it was last modified on Sun Mar 17 20:24:00 1996 - 28 days ago
250 CWD command successful.
250 was last modified on Sun Dec 10 15:01:00 1995 - 126 days ago
250-Please read the file README.descriptions
250- it was last modified on Sun Dec 10 15:01:00 1995 - 126 days ago
250-Please read the file README.dir-list
250- it was last modified on Fri Mar 29 11:25:00 1996 - 16 days ago
250-Please read the file README.file-formats
250- it was last modified on Sun Dec 10 15:02:00 1995 - 126 days ago
250-Please read the file README.how-to-upload
250- it was last modified on Sun Mar 17 20:37:00 1996 - 28 days ago
250-Please read the file README.mirror-sites
250- it was last modified on Sun Mar 17 20:29:00 1996 - 28 days ago
250-Please read the file README.simtel-cdrom
250- it was last modified on Sun Mar 17 20:24:00 1996 - 28 days ago
250 CWD command successful.

Subsequently, you can type the "ls - l" command at the "ftp" prompt, as shown below, to see the directory contents as shown in Fig.5-6 and Fig.5-7:

ftp> ls-l

Fig.5-6 Response to "ls-l" command

200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
total 7393
-rw-r--r-- 1 jeff OAK 183 Dec 10 14:59 .message
-rw-r--r-- 1 jeff OAK 183 Dec 10 14:59 .msg
-rw-r--r-- 1 jeff OAK 0 Jan 28 1995 .notar
-rw-r--r-- 1 jeff OAK 0 Jan 28 03:56 123456
drwxr-xr-x 2 jeff OAK 8192 Mar 29 00:43 4dos
-rw-r--r-- 1 jeff 79 11728 Mar 29 11:25 DIRLIST.TXT
-rw-r--r-- 1 jeff 79 100 Apr 13 11:40 FILES.IDX
-rw-r--r-- 1 jeff OAK 4706 Dec 10 15:00 README.COPYRIGHT
-rw-r--r-- 1 jeff OAK 1685 Dec 10 15:01 README.MIRRORING
-rw-r--r-- 1 jeff OAK 11716 Dec 10 15:01 README.descriptions
-rw-r--r-- 1 jeff 79 11728 Mar 29 11:25 README.dir-list
-rw-r--r-- 1 jeff OAK 9019 Dec 10 15:02 README.file-formats
-rw-r--r-- 1 jeff OAK 3238 Mar 17 20:37 README.how-to-upload
-rw-r--r-- 1 jeff OAK 7959 Mar 17 20:29 README.mirror-sites
-rw-r--r-- 1 jeff OAK 2927 Mar 17 20:24 README.simtel-cdrom
-rw-r--r-- 1 jeff 79 391303 Apr 11 20:01 SIMINDEX.ZIP
-rw-r--r-- 1 jeff 79 366568 Apr 10 15:40 SIMLIST.ZIP
-rw-r--r-- 1 jeff OAK 43691 Aug 31 1994 UNZIP.EXE
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:53 ada
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:45 ai
drwxr-xr-200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
total 7393
-rw-r--r-- 1 jeff OAK 183 Dec 10 14:59 .message
-rw-r--r-- 1 jeff OAK 183 Dec 10 14:59 .msg
-rw-r--r-- 1 jeff OAK 0 Jan 28 1995 .notar
-rw-r--r-- 1 jeff OAK 0 Jan 28 03:56 123456
drwxr-xr-x 2 jeff OAK 8192 Mar 29 00:43 4dos
-rw-r--r-- 1 jeff 79 11728 Mar 29 11:25 DIRLIST.TXT
-rw-r--r-- 1 jeff 79 100 Apr 13 11:40 FILES.IDX
-rw-r--r-- 1 jeff OAK 4706 Dec 10 15:00 README.COPYRIGHT
-rw-r--r-- 1 jeff OAK 1685 Dec 10 15:01 README.MIRRORING
-rw-r--r-- 1 jeff OAK 11716 Dec 10 15:01 README.descriptions
-rw-r--r-- 1 jeff 79 11728 Mar 29 11:25 README.dir-list
-rw-r--r-- 1 jeff OAK 9019 Dec 10 15:02 README.file-formats
-rw-r--r-- 1 jeff OAK 3238 Mar 17 20:37 README.how-to-upload
-rw-r--r-- 1 jeff OAK 7959 Mar 17 20:29 README.mirror-sites
-rw-r--r-- 1 jeff OAK 2927 Mar 17 20:24 README.simtel-cdrom
-rw-r--r-- 1 jeff 79 391303 Apr 11 20:01 SIMINDEX.ZIP
-rw-r--r-- 1 jeff 79 366568 Apr 10 15:40 SIMLIST.ZIP
-rw-r--r-- 1 jeff OAK 43691 Aug 31 1994 UNZIP.EXE
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:53 ada
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:45 ai
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:50 animate
x 2 jeff OAK 8192 Mar 27 23:50 animate


What we have got in Fig.5-6 is a partial alphabetical listing of subdirectories that contain programs. After removing many subdirectories which were listed, the remaining listing is shown in Fig.5-7.

Fig.5-7 Continuation of the "ls-l" command response

rwxr-xr-x 2 jeff OAK 8192 Mar 27 23:49 wordperf
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:57 worldmap
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:57 wpj_mag
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:52 wwiv
drwxr-xr-x 2 jeff OAK 8192 Apr 12 02:07 x_10
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:50 xlisp
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:57 xwindows
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:47 zip
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:53 zmodem
drwxr-xr-x 2 jeff OAK 8192 Mar 27 23:57 zoo
226 Transfer complete.


As you can see, there are a large number of sub-directories in the msdos directory. You can pick the area of your interest and scan the directory to determine the file you may want to download. As mentioned earlier, there is usually a readme file in the directory, giving one-line descriptions for each item, for your guidance.

ftp> bye

221 Goodbye.

So, now you know how to log on to an ftp site, maneuver yourself to different directories, and get a directory listing. We have yet to do something useful once we are there.

5.3 Reading a text file at an ftp site

Ftp can only transfer files, not read their content, so you would normally have to wait until you have transferred the file to your account at VSNL, in order to see what is in it. However, there is a little-known trick to read a file without leaving the ftp site, by giving the command "get README | more" at the "ftp>" prompt, as shown below.

ftp> get README |more

This will display the contents of the text file page by page on your screen. It is very important to be able to do this. To go to the next page, press spacebar.

5.4 Getting a file to your account at VSNL

Now you are ready to transfer a file from the remote server to your account. To accomplish this you have to decide if the file is a text file or a binary (computer program, coded e.g. MSWord, or any compressed) file as you need to use the appropriate method for each type of file. For a simple text file, the transfer command will be:

ftp> get filename

For a computer program, the transfer command is:

ftp> bin

Press <Enter> after the transfer command. This tells the ftp site and your host site that you are sending a binary file, i.e., a program. Most ftp sites now use binary format as a default, but it's a good idea to use this, in case you've connected to one of the few that doesn't.

Then issue the command to get the file:

ftp> get filename

The file will now be transferred to your account at VSNL. To get it to your computer, you will need to do a file download, a topic discussed in Chapters 11 & 13.

Suppose you want to transfer the file from your account to another computer. The command for this is "put filename", given after the "ftp>" prompt, which is the reverse of the get command and functions exactly like it.

There are other important commands which are used quite frequently. These are listed in the second column of Table below, and the resulting action is given in the first column.

Table. of frequently-used ftp commands

To do this on ftp prompt Type this
   
List current directory ls-l, dir
List another directory dir directory name
Change directory cd directory
Prepare to download text file ascii
Prepare to download not-text file binary or image or bin
Download a file get filename
Download many files mget file1 file2....
Upload a file put filemane
Upoad many files mput file1 file2....
Delete a remote file del filename
Leave ftp bye or quit

Of course there are many more commands but the above-mentioned ones are used most often, by most of us.

5.5 Odd letters - Decoding file endings

Files are commonly stored in compressed form. There are a wide variety of compression methods in use, and most of these decompression programs can be located through "archie". You can tell which method was used by the last one to three letters at the end of a file name. Here are some of the more common ones, with instructions regarding how to un-compress the respective file.

.txt or .TXT By itself, this means the file is a document, rather than a
program.
.ps or .PS A PostScript document, in Adobe's page description
language. You can print this file on any PostScript
capable printer, or use a previewer, like GNU project's GhostScript.
.doc or .DOC Another common "extension" for documents. No decompression is needed, unless it is followed by:
.Z This indicates a Unix compression method. To uncompress,
type uncompress filename.Z and hit enter at your host system's command line. If the file is a compressed text file, you can

u16.zip is a MS-DOS program that will let you download such a file and uncompress it on your own computer. The Macintosh equivalent program is called MacCompress. Use archie to find these.alternatively read it online by typing zcat filename.txt.Z |more

.zip or .ZIP These indicate the file has been compressed with
a common
MS-DOS compression program, known as PKZIP. Use archie to find PKZIP204.EXE. Many Unix systems will let you un-ZIP a file with a program called, well, unzip.
.gz A Unix version of ZIP. To uncompress, type gunzip filename.gz at your host system's command line.
.zoo or .ZOO A Unix and MS-DOS compression format. Use a
program called
zoo to uncompress.
.Hqx or .hqx Mactintosh compression format. Requires the
BinHex program.

.shar or Another Unix format. Use unshar to uncompress .Shar
.tar Another Unix format, often used to compress several related files into one large file. Most Unix systems will have a program called tar for "un-tarring" such files. Often, a "tarred" file will also be compressed with the gz method, so you first have to use uncompress and then tar.
.sit or .Sit A Mactinosh format that requires the StuffIt
program.
.ARC Another MS-DOS format, which requires the use of the ARC
or ARCE programs to extract the information from the compressed file.
.LHZ Another MS-DOS format; requires the use of LHARC to extract the information from the compressed file.

A few last words of caution: check the size of a file before you get it. The Net moves data at phenomenal rates of speed. But the 500,000-byte file that gets transferred to your host system in a few seconds could take more than an hour or two to download to your computer, if you're using a 2400-baud modem, or if your telephone connection to VSNL is so poor that the modem speed gets adjusted down to 1200 baud for example. Your host system may also have limits on the amount of bytes you are allowed to store online, at any one time. Furthermore, although it is extremely unlikely you will ever get a file infected with a virus, if you plan to do much downloading over the Net, you'd be wise to invest in a good anti-viral program, just in case.

5.6 Your friend 'archie'

How do you find a file you want, though?

Until a few years ago, this could be quite a pain -- there was no master directory to tell you where a given file might be stored on the Net. Who'd want to slog through hundreds of file libraries looking for something?

Alan Emtage, Bill Heelan and Peter Deutsch, students at McGill University in Montreal, asked the same question. Unlike the others, though, they did something about it. They created a database system, called 'archie', that periodically calls up file libraries and basically finds out what they have available. In turn, anybody can dial into archie, type in a file name, and see where on the Net it is available. Archie currently catalogs some 1,000 file libraries around the world.


Today, there are three avenues to ask archie to find a file for you:

Telnet,


A "client" Archie program on your own host system, or

All three methods let you type in a full or partial file name and will tell you where on the Net it's stored.

If you have access to telnet, you can telnet to one of the following addresses:

archie.mcgill.ca

archie.sura.net

archie.unl.edu

archie.ans.net

archie.rutgers.edu

If asked for a log-in name, type

archie

and press <Enter>.

When you connect, the key command is prog, which you use in this form:

prog filename

followed by <enter>, where "filename" is the program or file you're looking for. If you're unsure of a file's complete name, try typing in part of the name. For example, "PKZ" will work if you are searching for "PKZG204.EXE." The system does not support DOS or Unix wildcards (asterisks in place of parts of a filename). You can use archie to search for, say, everything online related to the Beatles, as well as computer programs and graphics files.

archie -s filename |more

will stop the output every screen (handy if there are many sites that carry the file you want). Or you could open a file on your computer with your text-logging function.

Fig.5-8 shows a transcript of an online session at VSNL to search for the file pkzip.exe: From the first Main Menu make a selection of item "3", telnet service and proceed as follows:

Fig. 5-8 Opening a archie session

telnet> o archie.sura.net
Trying 192.239.16.130...
Connected to kadath.sura.net.
Escape character is '^]'.

SunOS UNIX (kadath.ser.bbnplanet.com)
login: archie
# Bunyip Information Systems, Inc., 1993, 1994, 1995
# Terminal type set to `vt100 24 80'.
# `erase' character is `^?'.
# `search' (type string) has the value `sub'.
archie> prog pkgzip.exe

The following are the results of the search by "archie". As the total number of sites is very large, we are listing only a representative sample in Fig.5-9:

Fig.5-9

# Search type: sub, Domain: northamerica.
# Your queue position: 1
# Estimated time for completion: 5 seconds.
working... =O=O=O=
Host cattell.psych.upenn.edu (130.91.68.122)
Last updated 03:36 11 Apr 1996
Location: /incoming/kathy
FILE -rw-rw-r-- 41293 bytes 23:05 29 Mar 1996 pkzip.exe
Host ftp.ftp.com (128.127.1.128)
Last updated 04:48 1 Apr 1996
Location: /support/testing
FILE -rw-rw-r-- 42166 bytes 14:32 13 Mar 1996 pkzip.exe
Host gopher.emr.ca (132.156.36.1)
Last updated 03:12 14 Apr 1996
Location: /pub/incoming/tracplts
FILE -rw-rw-r-- 42166 bytes 13:57 7 Mar 1996 pkzip.exe
Host ftp.csc.ncsu.edu (152.1.58.11)
Last updated 03:56 6 Apr 1996
Location: /for_scott
FILE -rw-r--r-- 42166 bytes 07:41 15 Feb 1996 pkzip.exe
.
.
etc.


The third way, for people without access to either of the above, is e-mail. Send a message to

archie@quiche.cs.mcgill.ca

You can leave the subject line blank. Inside the message, type

prog filename


where filename is the file you're looking for. You can ask archie to look up several programs by putting their names on the same "prog" line, like this:

prog file1 file2 file3

Within a few hours, archie will write back with a list of the appropriate sites.

In all three cases, if there is a system that has your file, you'll get a response that looks something like this:

Host sumex-aim.stanford.edu

Location: /info-mac/comm

FILE -rw-r--r-- 258256 Feb 15 17:07 zterm-09.hqx

Location: /info-mac/misc

FILE -rw-r--r-- 7490 Sep 12 1991 zterm-sys7-color-icons.hqx

Chances are, you will get a number of similar looking responses for each program. The "Host" is the system that has the file. The "Location" tells you which directory to look in when you connect to that system. Ignore the funny-looking collections of r's and hyphens for now, as they have something to do with file permissions. After these comes the size of the file or directory listing in bytes, the date it was uploaded or updated, and the name of the file.

a) Archie sites accessible by Telnet:

The following are few of the Archie servers that you can access using telnet. Please use the username

archie

to login, use server closest to you:

Telnet

Site location
   
archie.au Australia
archie,edvz.uni-linz.ac.at. Austria
archie.univie.ac.at Austria
archie.uqam.ca Canada
archie.cs.mcgill.ca Canada
archie.funet.fi Finland
archie.univ-rennes1.fr France
archie.th-dramstadt.de Germany
archie.ac.il Isreal
archie.unipi.it Italy
archie.wide.ad.jp Japan
archie.hana.nm.kr Korea
archie.sogang.ac.kr Korea
archie.uninett.no Norway
archie.rediris.es Spain
archie.luth.se Sweden
archie.switch.ch Switzerland
archie.ncu.edu.tw Taiwan
archie.doc.ic.ac.uk United Kingdom
archie.hensa.ac.uk United Kingdom
archie.unl.edu USA(NE)
archie.internic.net USA(NJ)
archie.rutgers.edu USA(NJ)
archie.ans.net USA(NY)
archie.sura.net USA(MD)


To start an archie search using an archie server that you have telnetted to, type

find <searchterm>

replacing <searchterm> with what you want the server to search for (see example above).

After Archie has finished its search and printed its results on your screen, you can have Archie e-mail the results to you by typing:

mail <your Internet address>

replacing <your Internet address> with our full e-mail address. To quit the telnet session type quit at the prompt.

b) Accessing Archie By e-mail

You can conduct archie search by e-mail. To do so send an e-mail to the Archie server closest to you:

Archie mail address Location

archie@archie.au Australia
archie@archie.advz.uni-linz.ac.at Austria
archie@archie.univie.ac.at Austria
archie@archie.uqam.ca Canada
archie@archie.mcgill.ca Canada
archie@archie.funet.fi Finland
archie@archie.univ-rennes1.fr France
archie@archie.th.darmstadt.de Germany
archie@archie.ac.il Israel
archie@archie.unipi.it Italy
archie@archie.wide.ad.jp Japan
archie@archie.hana.nm.kr Korea
archie@archie.sogang.ac.kr Korea
archie@archie.uninett.no Norway
archie@archie.rediris.es Spain
archie@archie.luth.se Sweden
archie@archie.switch.ch Switzerland
archie@archie.ncu.edu.tw Taiwan
archie@archie.doc.ic.ac.uk United Kingdom
archie@archie.hensa.ac.uk United Kingdom
archie@archie.unl.edu USA(NE)
archie@archie.internic.net USA(NJ)
archie@archie.rutgers.edu USA(NJ)
archie@archie.ans.net USA(NY)
archie@archie.sura.net USA(MD)

Top of the Chapter
Chapter 4 Using E-mail (Electronic Mail)
Chapter 6 TELNET
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