Skip to main content

The interface and the Terminal

Table of contents​

  1. Graphical interface vs command line
  2. Why the terminal is essential
  3. Opening and using the terminal
  4. Anatomy of the prompt
  5. First steps in the terminal

1 - Graphical interface vs command line​

Two ways to interact with Linux​

Comparison​

AspectGraphical Interface (GUI)Command Line (CLI)
LearningIntuitiveRequires training
SpeedSlow (mouse)Fast (keyboard)
AutomationDifficultEasy (scripts)
ResourcesHeavyLightweight
Remote accessComplexSimple (SSH)
PrecisionLimitedTotal
ServersRarely availableAlways available

Concrete example​

Create 100 folders named projet_1 to projet_100:

In GUI: Right-click → New folder → Name → Repeat 100 times... ⏱️ ~30 minutes

In CLI:

mkdir projet_{1..100}

⏱️ 1 second!

tip

The command line may seem intimidating at first, but it quickly becomes indispensable. It's an investment that pays off enormously!

🔝 Back to table of contents​


2 - Why the terminal is essential​

Practical reasons​

In the professional world​

ContextWhy the terminal?
ServersNo graphical interface
CloudSSH access only
DockerCommand-line commands
CI/CDAutomated pipelines
Kuberneteskubectl on the command line
AnsibleAutomated configuration

What the terminal allows​

  1. Automate repetitive tasks
  2. Administer remote servers
  3. Diagnose problems quickly
  4. Process large amounts of data
  5. Integrate into DevOps pipelines
warning

In the DevOps world, 95% of your work is done on the command line. Mastering the terminal is not optional!

🔝 Back to table of contents​


3 - Opening and using the terminal​

On Ubuntu Desktop​

Method 1: Keyboard shortcut (recommended)

Ctrl + Alt + T

Method 2: Menu

  • Click "Activities" (top-left corner)
  • Type "Terminal"
  • Click the Terminal icon

Method 3: Right-click

  • Right-click on the desktop
  • "Open a terminal"

On WSL2 (Windows)​

Method 1: Start menu

  • Search for "Ubuntu"
  • Click the Ubuntu application

Method 2: Windows Terminal (recommended)

  • Install Windows Terminal from the Microsoft Store
  • Open Windows Terminal
  • Select Ubuntu from the tabs

Method 3: Command

# Dans PowerShell ou cmd
wsl

The terminal interface​

┌─────────────────────────────────────────────────────────┐
│ Terminal                                          - □ x │
├─────────────────────────────────────────────────────────┤
│                                                         │
│ user@ubuntu:~$                                          │
│                                                         │
│                                                         │
│                                                         │
│                                                         │
│                                                         │
└─────────────────────────────────────────────────────────┘

🔝 Back to table of contents​


4 - Anatomy of the prompt​

The prompt is the command line that awaits your instructions.

Structure of the prompt​

user@hostname:~$
│    │        │ │
│    │        │ └── $ = utilisateur normal (# = root)
│    │        └──── ~ = répertoire courant (home)
│    └───────────── hostname = nom de la machine
└────────────────── user = nom d'utilisateur

Prompt examples​

PromptMeaning
john@ubuntu:~$John, on ubuntu, in his home
john@ubuntu:/etc$John, on ubuntu, in /etc
root@server:/#Root (admin), in / (root)
deploy@prod:/var/log$The deploy user, in /var/log

Important symbols​

SymbolMeaning
$Normal user
#Root user (administrator)
~The user's home directory
/Root of the file system
.Current directory
..Parent directory
danger

When you see # instead of $, you are in root mode (administrator). Be very careful, you can break everything!

The cursor​

The blinking cursor indicates where your text will be typed:

user@ubuntu:~$ █
              └── Curseur clignotant

🔝 Back to table of contents​


5 - First steps in the terminal​

Your first command​

Type this command and press Enter:

echo "Bonjour, Linux !"

Result:

Bonjour, Linux !

echo displays the text you give it.

Basic commands to try​

# Afficher la date et l'heure
date

# Afficher le calendrier du mois
cal

# Afficher qui vous êtes
whoami

# Afficher le nom de la machine
hostname

# Afficher le répertoire courant
pwd

# Effacer l'écran
clear

Essential keyboard shortcuts​

ShortcutAction
TabAuto-completion
↑ / ↓Command history
Ctrl + CCancel the current command
Ctrl + LClear the screen (like clear)
Ctrl + AGo to the beginning of the line
Ctrl + EGo to the end of the line
Ctrl + UDelete the line before the cursor
Ctrl + RSearch in the history

Auto-completion with Tab​

The Tab key is your best friend:

# Tapez "wh" puis Tab
wh[Tab]
# Affiche les commandes commençant par "wh" :
# whatis  whereis  which  while  who  whoami

# Tapez "whoa" puis Tab
whoa[Tab]
# Complète automatiquement en "whoami"

Command history​

# Voir les dernières commandes
history

# Voir les 10 dernières
history 10

# Réexécuter la dernière commande
!!

# Réexécuter la commande numéro 42
!42

# Rechercher dans l'historique
Ctrl + R puis tapez un mot

Hands-on exercise​

Try these commands in order:

# 1. Qui suis-je ?
whoami

# 2. Sur quelle machine ?
hostname

# 3. Quelle date ?
date

# 4. Où suis-je ?
pwd

# 5. Afficher un message
echo "Je suis sur $(hostname) en tant que $(whoami)"

# 6. Voir l'historique
history 5
Tip

Use the ↑ and ↓ arrows to navigate the history rather than retyping the commands!

🔝 Back to table of contents​


Key takeaways​

  • The terminal is more powerful than the graphical interface
  • The prompt shows user@machine:directory$
  • $ = normal user, # = root (be careful!)
  • The Tab key auto-completes
  • Ctrl + C cancels a running command
  • The history (up/down arrows) saves time

🔝 Back to table of contents​

← Previous chapter | Next chapter: Navigating the file system →