Logging into a unix machine
Logins from the console or an X-terminal
When you sit down at the console or an X-terminal you will
see a window that looks like this:
Login using your username and password.
Logins from telnet on a pc or mac
Type "telnet physics". It will prompt you for your username
and password. Once you have logged in, type
'setenv TERM "vt100"' (everything inside the single quotes)
if you are using csh or tcsh. Type 'TERM=vt100'
if you are using bash. See
the section on environment variables below to learn how
to find out which shell you are using.
Logins from telnet or rlogin on another unix machine
If you have setup a .rhosts file,
type "xon physics xterm" for an X11 graphics
window or type "rlogin physics" for a text window. Otherwise
type "telnet physics". It will prompt you for your username
and password. Once you have logged in, type
'setenv DISPLAY "computer_name:0"' (everything
inside the single quotes, substituting the name of the computer
you are logging in from in place of computer_name).
Type 'export DISPLAY=computer_name:0'
if you are using bash. See
the section on environment variables below to learn how
to find out which shell you are using.
How do I tell what kind of terminal I'm using?
Macs should be easiest to identify because somewhere on the
keyboard and case, they have a little apple logo. Unix boxes
are also easy to identify since they will either have a login
window like the one above or a login
prompt that looks like:
Linux version 1.2.1
login:
Obviously, if you can't login to the unix box, you don't have
premission to use the machine and you'll have to find somewhere
else to login. If there is a login window, you are using a
graphical workstation and will need to know the computer name
and how to enter this into the DISPLAY environment variable.
If there's just a login prompt or you typed "telnet physics" from
a mac or pc, you are using a text based workstation and will
need to know how to enter "vt100" into the TERM environment variable.
Environment Variables
Environment variables contain information that the unix operating
system uses to manage your session. You can see what the current
values are by typing "env". The three values that people
most often have to deal with are:
- SHELL -- You need to know the
value of this because it
the command that you use to set environment variables differs among
shells. If your SHELL environment variable says "csh" or "tcsh",
you use the command setenv VARIABLE "value" to set environment
variables. If your SHELL environment variable says "bash", you use
the command export VARIABLE=value to set environment variables.
- TERM -- This tells unix what kind
of terminal you are using.
If you are using a text based workstation, this value should be "vt100".
You can set it by saying setenv TERM "vt100" if your SHELL is
csh. If you are using a graphical workstation your TERM value should
be "xterm" and should have been set automatically when you logged in.
- DISPLAY -- This tells unix where
display your windows.
If you are using a graphical workstation your DISPLAY value should
be "computer_name:0" where you use the name of the computer in front
of which you're sitting. You can set this by typing
setenv DISPLAY=hyperfine.physics.wm.edu:0 if your SHELL is tcsh
and your computer's name is hyperfine.physics.wm.edu. Since it's on
our subnet you could just type hyperfine:0.
rhosts files
If in your root directory
on physics you put a file called .rhosts which contains the name of a
computer from which you often telnet to physics, the next time you want
to telnet to physics you will be able to rlogin instead. The rlogin
command doesn't prompt for your password. Because of this it can be
very dangerous. NEVER put the name of a pc or mac in your .rhosts file
and don't include the names of machines you rarely use. The .rhosts
file will also permit you to remotely open windows on physics without
actually logging in. Thus you can type xon physics xterm to
get an xterm on physics when you are logged in to another computer
with X-windows.
Last modified 9/14/95
College of William and Mary, Dept. of Physics
matt@physics.wm.edu