Getting started
Overview
Using UNIX
Usernames
Logging in
Logging
out
Commands
Typing in
commands
Commands and
options
Communication with other
users
Email
Other
communication facilities
Files
The editor Vi
Vi commands (command
mode)
Vi commands (colon mode)
Other editors
Input
and output
Scripts
Here-documents
Pipes
Making copies of input
and output
Pagers
Emergencies
Getting
help
Summary
Exercises
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Email
Although most people are familiar with email, through
sophisticated mail software such as Microsoft's Outlook or Eudora,
it is instructive to look at the basic facility available under
UNIX. This does still have uses, for example if you require a shell
program to send email without intervention from the user. The
standard utility for sending email is Mailx. To
make use of this, you need to know the username of the person you
wish to send a message to. Type mailx followed by the
username, and then type in the message terminated by
ctrl-D on a line of its own. If option -s is
given to mailx, the string following -s
will be used to denote the subject of the message to the
recipient. It is always good practice to give an email message a
subject, and if the subject string contains spaces, then it must be
enclosed in quotes. For example,
$ mailx -s "Programming Assignment" sam
Hello Sam.
Have you finished the assignment yet?
ctrl-D
will send a message to user sam. If you have a
tilde (the symbol ~) as the first character on any line you type
in, this will be interpreted by mailx as a management
instruction. For instance, if you wish to edit a message half-way
through typing it in, type ~v and you will then be
editing it using a standard text editor (usually Vi). If you have a
friend who is currently logged in, mail him or her a short message
and ask them to mail you one. If not, mail one to yourself. In
either case, the mail arrives almost instantaneously. In order to
read mail that has been sent to you, just type mailx
on its own. If you have mail that you have not read,
mailx will display a brief list of messages awaiting
you, with the date they were received, the name of the sender, and
the subject (if specified by the sender). For instance,
$ mailx
>N 1 sam Wed Jul 27 15:28 16/465 Programming Assignment
N 2 jo Thu Jul 28 19:33 77/1220
In this example, you have two messages (each message is given a
number), the first from user sam, the second from user
jo. The mail from sam has subject
Programming Assignment, is 16 lines long and contains
465 characters; that from jo was sent without a
subject specified, is 77 lines long, and contains 1220 characters.
While you are reading your mail, at any particular moment one
message is current, and may be read, deleted,
saved in a file, or edited. The > symbol indicates
that message number 1 is the current message. The command
p (print) will then display the current message on the
screen. If you type ? a screenful of help
messages will be displayed indicating the other commands you can
give to Mailx. Note that this mail is simple text, and does not
contain attachments, or HTML enhancements, which are now
commonplace. Most UNIX systems are equipped with a collection of
other (not POSIX) programs for electronic mail,
Elm, Mail, Mush,
Pine, and Xmail coming to mind.
These utilities are similar to Mailx, but the sophistication and
facilities vary. Check with your system administrator for the
preferred mail programs on your system, and if they differ from
Mailx for simple use. Most Web browsers also include commands to
let you send mail.
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