Rediscovering the Shell Prompt

Computing with Your Mouse: Rediscovering the Shell Prompt

Joe St Sauver, Ph.D.
Director, User Services and Network Applications
joe@uoregon.edu

A common misconception is that everything that's on the Internet is on the World Wide Web. Others believe that if you want to use the Internet, you must click on things in a graphical user environment (such as Internet Explorer running under Windows).

Well, that's just not the case. There's a whole other world out there, just waiting for you to discover it, if you don't mind typing a little--it's the world of the Unix percent sign, or shell prompt. The shell prompt isn't for everyone, and if you're happy using what you've got you don't need to try it out. If you do try it, though, you may find you actually like it.

The following brief overview of Unix-speak is not meant to make you a shell prompt expert, it is just meant to alert you to some possibilities you may not otherwise be aware of.

Getting to the Shell Prompt

If you're a UO user, you should have an account on Darkwing (if you're a faculty member/staff person/grad student), or Gladstone (if you're an undergraduate student). This is the account you likely use for email, to dial in to the UO's modem pool, for wireless access, or for access to UO VPN or Blackboard.

To login to that Darkwing or Gladstone account, use ssh (secure shell):

Windows PC: On a PC running Windows, first make sure you've installed SSH Secure Shell from the PC Duckware CD-ROM, then see http://micro.uoregon.edu/security/ssh/shell.html
Macintosh: SSH is provided as part of Mac OS X. To use the integrated secure shell client to login to Darkwing or Gladstone, begin by opening a terminal window on your Mac, then enter either:

ssh -l yourusername darkwing.uoregon.edu

or

ssh -l yourusername gladstone.uoregon.edu

If this is the first time you're using SSH to connect, you will need to agree to accept the cryptographic credential associated with Darkwing or Gladstone. After that, you'll be prompted to enter the password for your account.

When you connect, you'll be working in a terminal window that emulates (or imitates) a Digital Equipment VT100-compatible terminal. (In the old days, before the advent of PCs, we old-timers actually used real VT100 terminals.)

Okay, I See a % Sign, Now What?

Once you see the percent sign prompt, you're ready to enter a Unix shell command. There are no menus and there's nothing to click on--you just need to know what commands to type.

One command that every user needs to know is logout (to logout from the shell prompt). Be sure to remember to always logout when you're done working at the shell prompt!

All Unix commands are case sensitive, and most Unix commands will be lowercase, rather short, and may not appear to be very adroitly named.

For example, to see documentation ("manual pages") describing Unix commands, you'd enter the man command at the percent sign prompt:

% man

But if you try that, don't be disappointed when all you see is:

usage: man [-] [-adFlrt] [-M path] [-T macro-package ] [ -s section ] name ... man [-M path] -k keyword ... man [-M path] -f file ...

If you're determined to learn more about the man command, try:

% man man

Again, you may be disappointed. Man pages are written in a very stylized way and are not particularly "user-friendly."

In general, you'll be better off trying one of the Unix books available from the Computing Center Documents Room, such as Harley Hahn's A Student Guide to Unix, or you can start with the very brief summary of common Unix commands at http://cc.uoregon.edu/basicunix.html

Editing Files

Before the advent of Microsoft Word, people created and edited text files using a "text editor" such as vi, emacs, or pico. Darkwing and Gladstone use two different such text editors by default:

On Darkwing, the default editor is vi, as described at http://cc.uoregon.edu/usingvi.html
On Gladstone, the default editor is pico, a simpler, menu-driven editor.

Reading Email Without Using Web Email, Eudora, or Outlook

You may be surprised to learn that you can read your email online at the percent sign prompt without using web email, Eudora, or Outlook. To do this, at the percent sign prompt simply enter pine:

% pine

The pine email program is menu driven, like the pico editor that Gladstone uses. (For more details on pine, see the handout "Using Pine for E-Mail" at http://cc.uoregon.edu/acrobatdocs/pine.pdf )

Looking at Web Pages From the Command Line

You can also look at web pages without using Internet Explorer, Mozilla, or some other graphical web browser. At the percent sign prompt, enter:

% lynx http://www.google.com/

to go to Google. You can move around using your arrow keys and search for a topic (such as "hockey") by typing it on the dotted line, then hitting the down arrow to "Google Search" and pressing return.

"Why Would I Want To Do This?"

At this point, you may be wondering, "Why on earth would I want to do stuff at the percent sign prompt?"

Working at the percent sign prompt is much like driving a car with a stick shift. Yes, driving a stick shift can be harder than driving an automatic transmission, but the stick shift may give you better control, or be cheaper, or may be the only option for specialized vehicles (such as large trucks), or driving a stick shift may just simply be more fun.

Working at the shell prompt can be much the same way: it can be quite efficient once you get the hang of it, and many people even find it rather satisfying. Using pine at the shell prompt largely eliminates the risk of getting a virus or worm in email, and using a command-line web browser (such as lynx) can make you sensitive to the issues that the visually impaired encounter when using a screen reader to access web pages.

We'd encourage you to get a good Unix book from the Documents Room (175 McKenzie Hall) and give it a try!

Summer 2004 Computing News | Computing Center Home Page