Reading the prompt and typing your first commands

The prompt is the shell's way of saying two things: "I am ready" and "here is where you are". On the practice machine it is short: ~%. On most Linux systems it is longer, something like ana@laptop:~$. Both carry the same information, just more or less of it.

Decoding the prompt

The practice machine keeps its prompt minimal: the current directory's name and a %. It does not show the usual # even though you are root, so do not rely on the symbol here; whoami is the honest answer. Watch the prompt change as you move: in lesson 5 you will see ~% become tmp% and then etc%.

Anatomy of a command line

A line is split on spaces into words. The first word is the command: a program to run, or a word the shell understands itself. The remaining words are passed to it. By convention, words starting with - are options (also called flags or switches) that change *how* the command behaves, and the rest are arguments, usually *what* it should act on. In ls -l /tmp, ls is the command, -l an option and /tmp an argument. Spaces matter: ls-l is one unknown word.

~% date
Sun Oct  4 18:52:18 UTC 2026
~% uname -a
Linux (none) 4.16.13 #13 SMP Sat Jul 21 13:56:18 CST 2018 i686 GNU/Linux
~% ls
~% touch hello.txt
~% ls
hello.txt
~% echo done
done

Six commands, read top to bottom. date prints the clock. uname -a prints everything uname knows: kernel, hostname (here the odd-looking (none)), version, build date and the i686 architecture. ls lists the current directory — empty at first, so it prints nothing and the prompt simply returns. touch hello.txt creates an empty file, and the second ls proves it. Silence is normal: most commands say nothing when they succeed.

When something goes wrong

Errors are short and specific. not found means the command name is wrong or the program is not installed. No such file or directory means an argument names something that does not exist — look for a typo in the path. invalid option means the dash-word is not one the command knows; lesson 7 shows how to look options up. Read the message, fix the one thing it names, and press Enter again. Nothing is damaged by a failed command.