Logging In To Your Unix Account

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Getting Your User ID

Before you access your Unix account, you will have to get your Unix account! Go to Room 200 of I Building and use one of the Express Terminals to find out your account name (user ID). Be sure the account is for qcunix1, not qcvaxa. If there are any problems, go down the hall to the information desk for help.

Background

Things might make more sense if you start by looking at some background material on accessing Unix accounts. That page will tell you about the various options you have for accessing your Unix account and will tell you the difference between command line mode and GUI mode.

Logging In

Using a PC in I Building

There are many PCs on campus that have an Ethernet connection to qcunix1, and you can use any of them to make a command line mode connection to your account. Some of the PCs in I Building Room 200 are set up to give you the option of accessing your account in either command line mode or in GUI mode, so we'll describe how to use those PCs since they provide the most general case.

At the present time, all the PCs in I-200 are configured for GUI mode, but only some of them (the AT&T brand PCs) operate with high-resolution video drivers that make the interface good.

Once you log into a PC you are given a menu of applications that you can run. Select Telnet to qcunix1 for command line access to your account, or Windows to bring up Microsoft Windows, from which you will be able to access your account in GUI mode.

Using Telnet

When you make a Telnet connection to your account you will be greeted with some messages followed by a login: prompt. Type in your user ID. Be sure to use the proper case (lower case) because upper and lower case letters are not interchangeable Unix. When prompted for your password, give your college ID number.

At this point you will be logged in, some intial commands will run automatically, and the shell will issue a prompt for you to enter commands. The prompt will be the string "qcunix1> ". You will be able to change the prompt if you want to, and in the examples we give, we will use "$ " to represent whatever prompt string you decide to use.

Using Windows (Microsoft and/or X)

If you select Windows instead of Telnet from the menu on the PC, Microsoft Windows will start running, and you will see the usual array of icons, including Netscape, displayed in the "Main" program group. One of the minimized program groups will be "eXcursion," which you should open by double clicking on it. In that program group you will find an icon for an application called "qcunix1 terminal." Double click on the "qcunix1 terminal" icon, and another application called eXcursion will start up, and you will then be asked for your User ID and password for your qcunix1 account. Enter them, and the next thing you will see will be a Microsoft Windows window that contains an X Window System window that is running the dxterm terminal application, which will provide you with a command line interface to a shell program running on your qcunix1 account. Got all that?

Once dxterm starts running, you will be in exactly the same situation as if you had logged in using Telnet. Some initial commands will run automatically, and you will get your "qcunix1> " command prompt. There is one major difference when you log in this way, though: You can now run X Window applications on qcunix1 and their windows will show up on your PC's Microsoft Windows screen. The secret to all this is eXcursion, which is an X Window System server that runs under Microsoft Windows.

For example, if you want to run two terminal sessions at the same time, it's no problem. Just type "dxterm &" at your qcunix1 command prompt and another window running another copy of dxterm will show up on your screen. Use the mouse to click on the window you want to work in. Also, if eXcursion is set up properly, you will be able to use Alt-<tab> to switch between dxterm windows. (Experiment with the left and right Alt keys: eXcursion should let Microsoft Windows know when you press one of them, and let X Window applications know when you press the other.)

Some other X Window applications you might want to try are "xlogo" and "nedit." You can use nedit to edit files as easily as you can with pico, and you can use the mouse to make editing even easier.

Dialing in

You can make a command line connection to your account from off-campus provided you have a modem and either a VT-100 compatible terminal or a terminal emulation program running on a PC. The Kermit terminal emulation program is available from the computer center.

The telephone number to dial is 718-997-5042. (2400 baud). When you get the "Enter Desitination" prompt, type "qcunix1" and you will be able to log in as described above. Except for the low baud rate, your access to your account will be the same as if you had chosen "Telnet" from one of the PCs on campus.

Set Your Password!

Your account can be accessed from any computer in the world that is on the Internet, and there are other people who would like to have access to it. Some of those people want to cause mischief, and some might want to take your work and claim it is their own. It's important to keep your account private.

The only way to protect your account is to use a password that is as secure as possible. You set your password with the passwd command. First, decide on the password you are going to use. It has to be easy for you to remember and to type, but it has to be hard for anybody else to guess. There are lots of rules about how not to choose a password: Don't use people's names or anything based on your User ID, don't use birthdays or other things based on dates, days of the week, etc. One popular form of password that is hard to guess combines two simple, but unrelated, words with a punctuation mark or number between them. Like everything else in Unix, your password is case-sensitive, and mixing upper and lower case letters can help make a password more secure.

When you enter the passwd command, it will prompt for your old password, and will have you enter the new password twice to make sure you got it right. If there is any problem with the password you chose, it will let you know. Note that the command is "passwd" rather than "password" -- Unix has traditionally used terse commands to save typing time.

Logging out

You log out of your account by exiting the shell program. There are three ways to do this:
  1. Type exit.
  2. Type quit.
  3. Type ^D (Control-D) at the command prompt.
  4. Hang up the phone if you are logged in through a modem.
Method (1) always works. Method (2) is almost equivalent, except that it will not work if the shell you are running is not the one that started up when you logged in. Unless you run another shell, methods (1) and (2) are pretty much equivalent. Method (3) is how you signal end-of-file in Unix, and if the shell receives that when it tries to read a command, it interprets it the same as an exit command. Method (4) is not a good idea, since there is a chance that you have programs running that the shell would remind you about if you log off using one of the other methods. However, you don't need to worry about someone else accessing your account if you use Method (4); you are automatically logged out any time your modem connection is broken.

Christopher Vickery
Queens College of CUNY
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