HyperTeamsThe terminal and commands
What you will learn What a terminal is and why it survives, how to read one command line, and the meaning of
command not found— where most people get stuck installing.
What the black window is
A terminal is a window where you instruct the computer in text. It does the same things clicking does. Only the method differs.
| Screen (GUI) | Terminal (CLI) | |
|---|---|---|
| Instruction | click | type |
| Learning | easy | you must know the name |
| Repeating | click it again, exactly | save one line, done |
| Recording | no trace of what you did | copy it and hand it over |
The bottom two rows are why it survives. Automation and reproducibility — what you did on screen can only be passed on as "click that thing over there", while a command pastes and does the same thing again. That is why this manual gives installation as a single line.
Opening it
| OS | Program |
|---|---|
| macOS | Terminal — search "Terminal" in Spotlight |
| Windows | PowerShell — "PowerShell" in the Start menu |
| Linux | Terminal |
You get a blinking line. That is where you type.
~ is shorthand for your home folder — it says you are currently there.
The shape of one command
Spaces are the separator. So a folder name containing a space must be quoted — the reason the previous chapter preferred hyphens.
Five things are enough
Narrowed to what this manual needs:
| Command | What it does |
|---|---|
cd <folder> | move into that folder |
ls (Windows dir) | list files here |
pwd | which folder am I in |
<command> --version | is it installed, which version |
Ctrl-C | stop what is running |
Ctrl-C is a key, not a command. It is the exit when something runs and will
not finish — the one you will use most.
Pasting may not be
Ctrl-V. macOS uses⌘V; Windows PowerShell uses right-click orCtrl-Shift-V.
command not found — most installation failures
This single line is the most common failure in Prerequisites.
It means "I could not find that command". Not installed and not found are different. A terminal does not search everywhere; it looks only in a fixed list of folders. That list is called PATH.
graph TD
A["you type claude"] --> B["search each folder in PATH"]
B -->|"found"| C["run it"]
B -->|"not found"| D["command not found"]Installers usually update PATH. But a terminal window that was already open does not know — it uses the list it read when it opened.
Spotting a dangerous command
A terminal rarely asks "are you sure?". Before pasting something from the internet, check these three.
Do not paste a command you do not understand. Asking an agent "explain what this command does" first is a good habit.
Common misconceptions
"Won't I break the computer with a terminal?"
Ordinary commands are safe. The dangerous ones are the three above, and they are equally dangerous through a graphical tool. The difference is only the missing confirmation dialog.
"Do I have to memorise commands?"
No. The five above carry you through this manual. The rest you look up when needed — which is what pages like the command reference are for.
Check yourself
1. Does command not found mean it is not installed?
Answer
Not necessarily. It means it was not found, and usually the install worked but PATH has not been re-read. Opening a new terminal is the first move.
2. Which key stops a running command?
Answer
Ctrl-C.
3. Why do folder names with spaces need quotes?
Answer
Because the terminal splits the line on spaces. Unquoted, it reads as two separate arguments.
Next, what those commands actually run → Programs and languages — Python, JavaScript, Node