 The Internet Postal Service 

Each day millions of mail messages traverse the Internet.
They are carried by a standard system called SMTP (Simple
Mail Transport Protocol), part of TCP/IP.  A term you will
often see if you use a Unix system is "mailer daemon."  This
is a program that runs in the background on your Unix system
works with SMTP to handle all the details of getting your
mail sent and delivered.

An important restriction imposed by SMTP is that it can only
handle TEXT data.  That is, character data, like the charac-
ters you can type on your keyboard.  To mail binary type
data it must first be encoded as text data.

 Standard Unix Mail 

There are mail programs much easier to learn and use than
the standard Unix mail program, such as Pine or Elm, but it
is good to know something about it because it is the only
mail program guaranteed to be on all Unix systems.  Even if
you do not have to use it, you may have to help someone who
does.  

Guess what the standard Unix mail program is called?  Right:
mail.  (Unix people have an imaginative flair).  To send mail
you simply type "mail" along with the address of the person
who is receiving the mail:  mail efudd@aol.com.  To read mail
you type the word "mail," and then pick from a list.

 Addressing Email 

To send mail to someone who uses a different host computer
than you address the message with the person's complete email
address:  mail walters@yorku1.york.edu.  As a rule, you may
omit parts of the subdomain address (the part following the
@) that you share in common with the addressee.  To send a
message to someone who uses the same host as you simply 
address the message with his/her userid:  mail efudd.  If you
incorrectly address email it cannot be delivered and it 
"bounces."  That is, it will be returned to your own mailbox
with a message from your local postmaster telling you that
the address is unknown.  For practice, let's log in and
send some mail...

 Review 

1) To mail a message type: mail [userid@useraddress].
2) Enter a subject or just press Enter when the subject
   line appears.  It is discourteous to send mail without
   a subject line.
3) Type your message a line at a time.  You cannot return
   to edit lines you have already entered without using a
   special trick.
4) Press Control-D to end text entry and send the message.
5) At the Cc: prompt enter the addresses of anyone you 
   would like to receive a copy of your message.  Separate
   them with spaces.
6) If you decide not to send a message, press Control-C twice.

 The Great Escape 
As you have seen, the mail program is line oriented.  This
means that after you press Enter at the end of each line 
you cannot edit the line.  It also means that you cannot 
access certain very convenient feature full screen programs
like Pine and Elm offer.  The (somewhat awkward) solution
to these problems is a set of commands you can enter from
within the mail program to invoke an editor, read in a file,
edit your mail header, etc.  They are called "escape commands"
because they must be entered as the first characters on a
line and preceded by the ~ (tilde) escape character.  There 
are many of them, but the most useful are: ~? - show all 
escape command; ~e - invoke editor; ~f - read in a message;
~r - read in a file; ~h - edit header lines; ~! - shell out.

 Reading Your Mail 

To read your mail first enter the command "mail."  If you 
have mail a numbered list will be printed on your screen.
If not you will receive a "no mail" message.  Each item on
the list will show who sent the message, when, how large
it is, and what the subject is (if your correspondent 
entered a subject line).  At the end of the list you will
see the "&" character.  This is the mail program prompt.
It means the mail program is ready to receive your commands.





 Mail Commands 
Mail commands are generally a single symbol followed by the
Enter key.  There are many of them, but here are the really
important ones:
   [number]     Display message #[number] from list
      +         Display next message
      -         Display previous message
      d         Delete current message
      s         Save current message
      r         Reply
      u         Undelete message
      q         Quit the mail program

Let's practice...

 Is This A Good Mail Program? 

No.  This is not a good mail program, but it works and in a
pinch it is essential to know it's commands.  It is far 
better to use one of the full screen programs like Pine.
Save the printed summary to this lesson.  It contains 
the mail commands and escape characters which you may
someday have to teach someone else.  In the mean time,
learn to use Pine.






 I Pine For Mail 

There are two things about mail:

     1) It's fun to get mail.
     2) It's fun to read other people's mail.

You can do both with a vengeance with Pine, the improved
Unix mail program that you will find most places.  Don't
even bother with the standard Unix mail command.  Much
about Unix is ugly, and the mail program is among the worst.

Fortunately, some friendly programmers have provided Pine.


 Mail, Mail Everywhere 

Pine is the easy way to be a world class communicator.  But
remember, when you start receiving truckloads of email, it's
your responsibility to keep your mailbox cleaned up.  If you
don't, people start to get mad at you.  And pretty soon you
stop getting mail because you're using up too much disk space.

But enough of the stern warnings.  With Pine it's easy to
manage your mail.  Let's log in and start Pine.





 Pinal Goodbye 

Now you know how to use Pine.  It makes email fun.
There is a great deal more to the Pine commands than we
have been able to cover here, but like all the resourcess
on the internet help is not far away.  From the Pine main
menu pressing the ? will call up help screens.

See you on the net.






 Mailing Lists 

There are thousands of ongoing discussion groups carried out
over the Internet via email.  They work by subscription.  
That is, if you have a special interest, you send your sub-
scription request to the person (or computer) that maintains
the mailing list in which you are interested and you are
added to the number who automatically receive the group's
common email each day.  You may then post your invaluable
insights to the group and read the less valuable insights
of others by simply using your email program.  It all works
automatically.  Some groups are moderated, meaning that 
someone controls what gets posted, but most are not.  Joining
a list is called "subscribing," but there is no charge.

 Maling Lists vs. Newsgroups

As you can tell, mailing lists and Usenet newsgroups have a 
lot in common, but with several important differences.
  1) To participate in a mailing list you do not have to
     learn a complicated news reader program.  It all works
     by email.
  2) Without any special effort on your part your messages
     simply appear each day in your mailbox.
  3) There tends to be far less "chatter" or "noise" among
     mailing lists than among newsgroups.  They seem to be
     more focused.
  4) Many important lists are moderated, or "owned" by some-
     one, oftentimes providing valuable guidance subscribers.

 What Lists Are Available? 

You name it and there is probably a list devoted to it--from
bagpipes and bee keeping to zephyrs and zebras.  How do you
find out about them?  Search a list of lists to find out 
what is available.

The simplest way is to gopher to sri.com and choose netinfo|
interest-groups.  You will be presented with an enormous list
of lists which you may search with the gopher "/" command.
This list is available by anonymous ftp from ftp.nisc.sri.com.
Dartmouth also maintains an exhaustive list for anonymous ftp
from dartcms1.dartmouth.edu in the "siglists" directory.  Get
the "read.me" file to obtain download instructions.

 Bitnet 

Bitnet is a widespread mostly academic network not part of the
Internet per se but with mail gateways to the Internet.  It is
important because many mailing lists are maintained on Bitnet.
They are called "listservs," after the programs that maintain
them.  You can get a list of all bitnet mailing lists by
sending a letter to any listserv with the command "list
global" in the body of the letter.  (The SRI and Dartmouth
lists contain Bitnet and Internet lists).  An Internet only
list of lists can be obtained via anonymous ftp from 
rtfm.mit.edu in the directory /pub/usenet/news.answers/mail/
maling.lists.


 How Do You Subscribe To A List? 

Let's say you have a passion for Shakespeare.  You gopher to
sri.com and search the list of lists.  You discover that
there is a list called SHAKSPER which is just what you are
looking for.  It's subscription address is "listserv@vm.
epas.utoronto.ca."  It's regular Bitnet address is SHAKSPER@
UTORONTO.CA.  (Bitnet addresses are often expressed in cap-
itals, as if Bitnet people are always shouting).  It is a 
moderated list, which means a human runs it, adds/deletes
users, and most importantly edits the postings.  You sub-
scirbe by simply sending a letter to the subscription ad-
dress with the only line in the body of your letter:
     subscribe SHAKSPER Yourfirstname Yourlastname

 Possible Problems 

On a moderated list like SHAKSPER you will have to respond
to the list moderator before being added to the list, but
most lists simply send you an acknowledgement and you 
begin receiving mail.

You may have a problem in sending messages to Bitnet 
addresses, however, if your provider is not set up to
automatically convert Internet style address to Bitnet
addresses.  If this is the case, you will have to send
your request to a Bitnet gateway (see printed summary).
The formula for addressing mail through a gateway is:
  gateway.address!computerid.bitnet!userID

 What Are Lists Like? 

If you are not sure you want to subscribe to a list
you view many of them via Usenet News.  In fact, all the
Bitnet listserv lists are posted to the "bit" hierarchy
of the newsgroups.  You can read them there to see if you
are interested (and get a feel for how active they are).

Many books provide annotated guides to the lists, but these
tend to get out of date even before the books are published.

There is also a list devoted to reviews of mailing lists.
It's address is lstrev-l@umslvma.


 Controlling Your Mailing Lists 

The best advice anyone can get who is new to automated mail-
ing lists is:  if you have an urge to subscribe, lie down
until it passes!  The vast riches of the lists invariably
temp the new user to oversubscribe.  If you belong to more
than 6 groups, you are receiving far more mail than you can
handle, because even a moderately active list can generate
dozens of messages each day.

The second best advice is:  keep the acknowledgement letter
you receive from the list immediately after subscribing.  It
contains valuable information on how to get off the list, to
hold your mail when you are on vacation, etc., etc.

 Mailing List Commands 
If you are subscribed to a Bitnet listserv, there is a set of 
uniform commands for controlling your mail (see printed sum-
mary).  Also, most Internet lists use similar commands.
There are many lists, however, that use custom commands.
That is why you must keep that first, valuable acknowlegement
letter.  Even if you don't read it at the time.  On certain
lists, unless you know the secret, it is nearly impossible to
GET OFF THE LIST.  Lists are littered with messages from
ignorant users who post requests such as "Please unsubscribe
me," "Please get me off this list," or a simple, plaintive
"Help."  All to no avail.  With a little effort on your part
this can be avoided and Internet Mailing Lists can be a
source of enlightenment and joy.











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