CD-ROM Today - The Disc! 3/CD-ROM_Today_The_Disc_3_August-September_1994.iso/inet/findfile.txt

Text File | 1994-01-31 | 11KB | 260 lines

 FINDING FILES BY E-MAIL ON THE INTERNET - THE SHORT COURSE
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 by Jack Rickard, Boardwatch Magazine, 12/93

Electronic bulletin board aficionados live in a world of files. When browsing
files to find the latest, newest, or just something interesting, the Internet
itself can't add or subtract much from the immense pool available on direct
dial bulletin boards. For one thing, the BBS community is way out in front on
the cataloging, listing, presentation, and description of shareware programs.

That said, the internet File Transfer Protocol (ftp) program is one of the
main uses of the Internet, and the bulk of network backbone traffic involves
the transfer of these files. Often, you will read in a USENET newsgroup, a
mailing list, or by e-mail of a specific file available from a specific site.
Usually, they provide three pieces of information:

 1. The site.
 2. The directory
 3. The file name.

With these three bits of information, you can locate and download a specific
file by ftp. You simply enter ftp sitename.org.whatever. You get a login
prompt and normally enter ANONYMOUS as the login, and your own e-mail address
as the password. You then enter the cd command to change to the directory (cd
/pub/somedir/thathas/somefil). And finally you enter GET
FILENAME.UNIX.FILES.CAN.BE.A LITTLE.LENGTHY.and.CaSe.SenSITive. This
transfers the file to your host. From most UNIX hosts, you then download the
file using the zmodem protocol by entering SZ FILENAME.EXT. The file is
transferred from the host, through the modems, to your local hard drive.

And this can be a very valuable thing to be able to do. Rather than list
every Internet provider in the world in an e-mail message, a correspondent
would be more likely to note its existence, and provide this pointer to the
larger file. Files containing Frequently Asked Questions (FAQ) are quite
commonly referred to in response to common questions in newsgroups. In this
way, files are maintained that anyone can ftp to learn the basics. Similarly
information files, electronic text articles, programs, and more are
maintained in "archives" and it is quite common to refer someone to one of
these files for more information, software, or lists of most anything.

The other common scenario is when you need to locate a file and have no idea
where it is. If you have the filename, or even part of the filename, you can
use a program titled ARCHIE to locate it. On most any host, you can enter
ARCHIE FILENAME. After a few seconds delay, the program will print a list of
sites, directories, and filenames where you can ftp the particular file you
are looking for. ARCHIE is actually a worldwide coordinated database of what
files are available where. It lists over a million files on thousands of
sites.

In this way, you can locate files, and obtain them. But it all assumes that
you have access to a full Internet host. Internet dialup accounts typically
run $15 to $25 per month. And realistically, for many of us, after the first
blush of enthusiasm for the Internet and a few weeks of "exploring", the bulk
of what we really want to do is e-mail, mailing lists, and newsgroups. There
is a growing number of users who have saved quite a bit of money by using
commercial services and bulletin boards for these services only.

And actually, there is quite a bit you can do from an e-mail only account.

LOCATING FILES

ARCHIE is actually quite usable by electronic mail, just slower. You can send
e-mail to an ARCHIE server, and receive the results back by electronic mail.
The following addresses are ARCHIE e-mail server sites.

 Australiaarchie.au
 Canadaarchie.mcgill.ca
 Englandarchie.doc.ic.ac.uk
 Finlandarchie.funit.fi
 Germany archie.th-darmstadt.de
 Israel archie.cs.huji.ac.il
 Japan archie.wide.ad.jp
 New Zealandarchie.nx
 Taiwanarchie.ncu.edu.tw
 United Statesarchie.rutgers.edu
 United Statesarchie.sura.net
 United Statesarchie.unl.edu
 United Statesarchie.ans.net

To use an ARCHIE e-mail server, address your message to ARCHIE @SITE.COM. For
example e-mail [e-mail]. Leave the SUBJECT blank. In the
body of the message on the first line, starting with the first character,
enter the command:

 prog filename.ext
 quit

The server will respond by e-mail with a list of sites and directories where
you can find that file.

There are a few other interesting commands.

 servers - returns a list of all known archie servers.

 site <site address> - returns a list of all files on a particular site.

 help - responds with a document describing how to use the server.

 path - allows you to specify a different address for the server to send the
 reply.

RETRIEVING FILES BY ELECTRONIC MAIL

Once you have located a file, you can actually retrieve it by electronic mail
as well - although this gets a little more complicated.

There are currently four general ftpmail servers available that will let you
retrieve a file from most any site, and will send it to you in electronic
mail form.

 United States [e-mail]
 England [e-mail]
 Australia [e-mail]
 France [e-mail]

These sites run a program titled FTPMAIL written by Paul Vixie at the Digital
Western Research Laboratory (decwrl.dec.com) that will generally go ftp a
file from any site, get the file, and mail it to you.

To use these sites, you basically make up a little batch file of what you
want it to do, and mail it to the ftpmail site in the message body.  The
basic form is as follows:

 connect pit-manager.mit.edu   ;ftp logon to the systemPIT-MANGER.MIT.EDU
 chdir pub/usenet/news.answers   ;change directories
 get finding-sources           ;get the file finding-sources
 quit                          ;end of the process

Note that you donÆt want to include the above comments - just the commands.

If the file you are looking for is a binary file instead of a text file, you
will want to instruct the server to send the file to you in UUENCODED format.
This is a process where the server converts the data into printable ascii
text. It makes them about a third larger, but assures that they can be
transported by e-mail. You will have to use the UUDECODE utility to
reassemble the message into the original binary file.

 reply [e-mail]
 connect time_a.timefreq.bldrdoc.gov
 binary
 uuencode
 chunksize 50000
 chdir /pub/acts
 get pctime.exe
 quit

If you send this message to [e-mail] you will receive the
PCTIME.EXE file back by electronic mail. The response may take from a few
hours to several days, depending on traffic at decwrl. The file will come
back in UUENCODED ASCII text form, and you will have to run UUDECODE on it to
get the PCTIME.EXE executable.

The first statement of the above procedure is the REPLY statement. This can
be used to specify the address you wish to have the file sent to. It isn't
actually necessary. Without it, the system will send the file to the return
address on your message. But the REPLY statement can be used to override your
return address, and does offer some additional insurance that the file is
mailed back to the correct address.

The CONNECT statement instructs the system to ftp to
time_a.timefreq.bldrdoc.gov. The BINARY statement sets the ftp mode to pass
binary files. UUENCODE tells it to encode the file as ASCII text for
transmission. CHUNKSIZE tells it to break the file into 50 kb messages. CHDIR
specifies the directory the file is stored in. GET PCTIME.EXE specifies which
file to send. QUIT terminates the batch procedure.

Note that files are limited to 100 KB in size, and that some intermediary
sites may further limit file size. Your host, such as CompuServe, may
typically limit message sizes to 50 KB. You can actually specify the maximum
message size with the statement CHUNKSIZE nnnnnn where nnnnn is the value in
bytes. The ftpmail server will break the file into a series of messages. You
will normally have to piece them back together with a text editor before
UUDECODING.

There are numerous other mail servers available. Unlike the FTPMAIL servers,
they tend to be specialized on particular topics or functions and operation
may vary from server to server. In general, to find out how to use a
particular server, simply send an e-mail message with the word HELP as the
message body. This will usually result in an electronic mail response with
documentation on how to use that particular server, and what is offered.

If it does not absolutely positively have to be there right now, you can
generally locate and retrieve most any file on the Internet from a simple
e-mail box with an domain name address.

 SOME ADDITIONAL MAIL SERVERS
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