Another novice question which should be directed to the newsgroup 
comp.unix.questions.  But novices can't know these things, so we should 
help them at least briefly:

Basic commands and concepts, originally submitted by haley@husc.harvard.edu.

Unix is an operating system, similar to MS-DOS, only much more powerful.
Some versions have over 300 commands in the basic system, not including
specialized applications. 

Command Primer
-------------- 
These commands are meant for use in a program called a "shell", which is
the user interface to the underlying programs that make up Unix. There are
several different shells which are widely used, so the prompts you see on
your screen, and the responses you see may vary slightly.  However, the
commands here should work in all of the shells. Note that users with
Graphical User Interfaces (X Windows, Openview, etc) may have to use the
"shelltool" or "command window" to use these commands. 

When you enter Unix commands, you will usually enter two or three words: 
the "command" itself, "modifier(s)" which change the way the command
works, and "argument(s)" which provide the command with additional
information.  Each word in the command is separated by a space, and
modifiers are preceded by a hyphen (-).  Here is an example of the "ls"
command with a modified and argument: 

Example:   command  modifier argument
           |        |        |
           ls       -CF      newdir

Typing this command will print a directory listing on your screen of the
directory "newdir".  The modifiers "-CF" tell the ls command to list other
directories listed with a / after them, and to list programs with a * after 
them, and logical links with a @ after them. 

The unix system uses a "hierarchical directory structure; to store files
on its disks.  This type of structure is like an upside-down tree, with
one "root" directory (like the root and trunk of a tree), and many
sub-directories (like branches) to store files in. Here is a small example
of what one might look like: 

             _______________(/)______________________________
            /      /           \       \                     \
          bin     lib           etc     home_____________     usr
                 /                     /        \        \
                sys              headcheese      \        headcheese3
                                                  \
                                                   headcheese2
                                                  /
                                           student
                                          /
                                     yourdir

The directories you must go through to find a particular file in "yourdir"
are "/" then "home" then "headcheese2" then "student" then "yourdir". In
Unix you call the directories you must go through to acces a file the
"path", and you type in the above path like this: 

/home/headcheese2/student/yourdir/filename

We call this "filename"'s "full path". The first "/" must be there for it
to be a full path. If you leave it off then the shell will assume it is a
"relative path" and look for the path to start in the directory you are
currently in, called the "current working directory". This is useful, as
always having to refer to files by their full path would get tedious. If
you were in "student" and wanted to refer to "filename" in "yourdir" you
could call it:

yourdir/filename

Or, if you are already in "yourdir", just

filename

O.K. That ought to be enough to get you interested and started...
Note to MS-DOS users: Unix has a hierarchical directory structure,
like MS-DOS, but uses a / to separate parts of a file path instead of
a \ (Back-slash).

Playing around
--------------
After you understand these things, the thing to do is *PLAY*. Look around
in the directories which store commands, and when you see something, do a
"man" on it. When you think you want to know more, a trip to a math
library is in order, or maybe a good bookstore. A good publisher is
O'reilly (Nutshell). Addison Wesley is also good, but I think they are
better for advanced stuff. 

Directories to look in: /bin /usr/bin /usr/local /usr/local/bin and just
about any other "*bin" directory. 

Note that this method is not time efficient at first. It is however MUCH
better for retention. I went from knowing nothing about Unix to having the
professor who got me started asking *me* for advice. 

There is a small hand-full of commands that you will use many times, and 
here they are...

man	Print out a manual page	on the screen.  If you know the name of a 
command, you can read the manual by typing "man command".  For example, 
typing "man ls" will display the manual for the ls command.  If you want 
to search all of the man pages for a certain word (on some systems), you 
can type "man -k word".  For example, typing "man -k mail" would list 
the names of all of the man pages pertaining to mail.
								man intro
passwd	Change your account password. This should be done the first time 
you log on, especially if you have no password. You must know your old
password to change it.  To change you password, type "passwd".  Then enter
your old (current) password, and the desired new password (twice).  Note 
that your passwords will NOT appear on the screen as you type them.

ls	List the contents of a directory.  Typing "ls" alone will list 
the contents of the current working directory.  If you want to see a 
specific directory, you can type "ls directoryname".  For example,
"ls /pub" will list the contents of the /pub directory (if there is 
one one your system).  Adding "-CF" options will give you a more 
detailed listing in columns, marking directories with a /, executable 
files with a *, and logical links with a @.  For example, typing "ls -CF"
will give a detailed listing of the current directory.

mkdir	Make a new directory as a sub-directory of where you are now.	
For example, "mkdir work" will create a sub-directory named "work" in 
your current directory.

cd	Change directory. Used to go up or down in the directory tree.
For example, to change to a sub-directory named "work" in the current 
directory, type "cd work".  Typing "cd .." will change to the parent 
directory, the directory one level above the current directory.

vi	 Invoke the vi editor. This is a screen editor, that is, a text editor
that makes use of the full screen. You must know this or another editor to
make use of "elm".  For those who use one of the windowing systems
exclusively, you can put off learning this as the windowing systems have
adifferent e-mail system.

rm	Remove a file. (note: this is forever! Think before you erase)
For example, to remove a file named "foo", type "rm foo".  Adding the 
"-r" option allows you to delete an entire sub-directory and ALL files 
and directories beneath it.  BE CAREFUL!  For example, to delete a 
directory named "work", and all files and sub-directories in "work", type 
"rm -rf work".

elm	Invoke the elm mail program.  Note: must know an editor
first.