By the end of this lesson you will be able to
- read the prompt and say what each part of it means
- run a command, give it options and arguments, and read its reply
- use
whoami,date,echo,clearandhistory - keep spaces in text with quotation marks
- bring back earlier commands with the up arrow and with
!
Every terminal on this page is a live pretend computer that runs inside your browser. Click inside one, type a command and press Enter. Nothing you type can harm your own computer. In each exercise, do the task and then press Check my answer. If you get stuck, Show solution shows one correct answer, and Reset puts the terminal back as it started.
Harriet's first morning
Harriet Cole has just joined Larkspur Press, a small publisher, as office assistant. The press keeps its manuscripts, invoices and records on one office computer called larkspur, and George Whitfield, the office manager, looks after it. On her first morning George pulls up a chair beside her.
“Most of what we do on this machine,” he says, “we do by typing. It looks bare at first, but it is quicker than clicking once you know a dozen commands. Let's start with the line you type on.”
The prompt
When the terminal is ready for you, it shows a prompt. On Harriet's computer it looks like this:
harriet@larkspur:~$
| Part | What it tells you |
|---|---|
harriet | who you are: the user name you logged in with |
@larkspur | which computer you are working on |
~ | which folder you are in. ~ is short for your own home folder. Module 2 is all about folders. |
$ | the shell is waiting for you. (It becomes # for the all-powerful root user, whom you will meet in Module 7.) |
Prompts vary from computer to computer, but they nearly always end in $ and nearly always show your name and folder somewhere. In these lessons we print commands after a $, with the computer's reply underneath. You never type the $ yourself: type only what comes after it.
Your first command: whoami
A command is a word, typed at the prompt and followed by Enter. The shell finds the program with that name, runs it, and prints whatever the program says. Try the simplest one there is. It prints your user name:
$ whoami harriet
Then try date, which prints today's date and the time:
$ date Mon Mar 2 09:00:07 UTC 2026
Your seconds will be different, because the clock moves on. Try both in the terminal below. You can type them, or press the buttons, which type for you.
Common mistake: capital letters
$ Date bash: Date: command not found
Linux treats capital and small letters as different, so Date and date are two different names, and only one of them exists. Nearly all commands are written entirely in small letters. The message “command not found” almost always means a typing slip, so look at what you typed before anything else.
Options and arguments
Many commands can be told what to do. Anything you type after the command's name, separated by spaces, is passed to it. There are two kinds:
- An option changes how the command works. Options usually begin with a dash, such as
-l, or with two dashes, such as--help. - An argument tells the command what to work on, such as a file name or a piece of text.
date takes a special kind of argument that starts with + and describes the layout you want. %F means “the full date, year first”, and %A means “the name of the day”:
$ date +%F 2026-03-02 $ date +%A Monday
The spaces matter. date +%F is a command and one argument; date+%F, with no space, is one long word that the shell cannot find.
Printing text: echo
echo prints back whatever you give it. That sounds pointless, but you will use it constantly: to write notes into files, to check what the shell will do with your typing, and to print messages from scripts.
$ echo Hello, Larkspur Press Hello, Larkspur Press
Each word after echo is a separate argument, and echo prints them with one space between each. So extra spaces vanish:
$ echo Room 4 Room 4 $ echo "Room 4" Room 4
In the second command the quotation marks tell the shell that everything inside them is one single argument, spaces and all. You will need quotes whenever text contains spaces or characters that mean something special to the shell, such as *, & or ;. Single quotes 'like this' work too, and are even stricter: the shell changes nothing at all inside them. Use single quotes for text containing !, because inside double quotes the shell still treats ! as a way of recalling an earlier command (you will see why at the end of this lesson). If you forget the closing quote, the shell waits for more with a > prompt. Type the closing quote and press Enter to finish.
Clearing the screen and looking back
When the screen gets crowded, clear wipes it (Ctrl+L does the same). Nothing is lost: the shell remembers every command you have typed. history lists them with numbers (the history command itself is the newest entry):
$ history
1 whoami
2 date
3 echo Hello, Larkspur Press
4 history
There are three quick ways to repeat a command:
| You type | What happens |
|---|---|
| the up arrow key | brings back the previous command so that you can edit it or press Enter to run it again. Press it again to step further back, and the down arrow to come forward. |
!! | runs the last command again |
!2 | runs command number 2 from the history list again |
When you use !, the shell first prints the command it is about to run, so that you can see what happened. The up arrow is the one you will use most, dozens of times a day.
Everything in this lesson works the same way in a terminal on any Linux computer, and in the terminals of most other modern computers too. The practice terminal's clock is fixed to a Monday morning in March, so its dates will not match your calendar.
Exercises
Each exercise starts with a fresh terminal. Read the task, type your commands, then press Check my answer.
Exercise 1 · Who and when
George asks Harriet to check that she is logged in under her own name. Run the command that prints your user name, and then the command that prints the date and time.
Exercise 2 · Say it with echo
Use echo to print this line exactly, with its capital letters and full stop:
Good morning from Larkspur Press.
Exercise 3 · Keep the spaces
The label on the stationery cupboard must have five spaces between the word and the number, like this:
Shelf B
Print it with echo, keeping all five spaces.
Exercise 4 · Today in a tidy format
George names his daily notes with the date written year first, like 2026-03-02. Make date print today's date in exactly that form, and nothing else.
Exercise 5 · Once more, from the history
Someone has already used this terminal. Look at the list of earlier commands, find the one that printed a message about the print queue, and run it again without typing the message out yourself. Use the up arrow, !! or ! with a number.
Quick check
Four questions to confirm the main ideas. Choose an answer to see the explanation.
The prompt reads harriet@larkspur:~$. What does the ~ tell you?
~ is the short name for your home folder, and the prompt shows the folder you are in.
What does echo Room 4 print (with five spaces typed, and no quotation marks)?
Without quotes the shell splits the text into two words, and echo prints them with a single space between. Quotation marks keep the spaces.
You type Whoami and see command not found. Why?
Linux treats capital and small letters as different. Whoami is a different name, and no program has it.
What does !! do?
!! repeats the previous command. history shows the list, and clear clears the screen.
Summary
- The prompt shows who you are, which computer and which folder, and ends in
$when the shell is waiting for you. - A command is a name followed by options (which change how it works, such as
-l) and arguments (which say what to work on). whoamiprints your user name,datethe date and time, andechoprints its arguments back.- Commands are case-sensitive. Quotation marks keep text with spaces together as one argument.
clearwipes the screen.historylists earlier commands; the up arrow,!!and!Nrun them again.
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