Think of a computer as an obedient servant: we give it commands, it obeys. The goal of these lessons is to learn to "speak Unix", the language in which we shall command our servant.
Let us begin with a simple command: we want the computer to tell us today's date. Here is how to do it:
% date Fri Mar 25 09:24:30 MST 1994
Wasn't that easy? Note that your commands --- what you tell the computer to do --- are displayed in bold. What the computer replies is displayed like this. Note also that you didn't type " % ": that is the prompt that the computer types. It does this when it is listening for your next command. (Prompts can be different from " % ")Try the "date" command now.
Here are some more commands to try, with samples of how the computer might respond.
% whoami jeremy
whoami displays the login name of the current user, who (for the purpose of these lessons) is "jeremy. " Try this now. The computer should respond with your login name.
% echo This is a test This is a test.
echo does just that: it tells the computer to retype the string "This is a test". Here is another use of echo:
% echo $PRINTER b129lab1
This time echo tells us what is stored in the PRINTER variable --- the name of the printer the computer will use if you print something. Capitalization is important in Unix, so be sure to say "PRINTER", not " printer" or "Printer". The dollar sign in front of the variable name is also important. Note what happens if we forget to use it:
% echo PRINTER PRINTER
Try all the examples above. Also: know where your printer is!
This is as good a time as any to introduce a little computer jargon. The words of the string "This is a test" are arguments to the command echo. The results of a command depend on what the arguments are.
Write down on a sheet of paper the names of all the commands you have used in this lesson. Carry it around with for a few days, and use it to review the commands several times. Do this both at a workstation and away from it. Finally, explain to a coworker or fellow student what the commands do. Do this at a workstation so you both can try things out.