tdtdt/pages/linux101.md

title : Linux 101 author: zvevqx published: 2025-11-22 cat: linux desc: ws

...

learn more about ssh -> https://www.ssh.com/ssh/

• linux :

start terminal ctrl + alt + t

ssh -p portnumber pi@ipaddress
ssh user @ distant_server.address : connection_port (default to 22 )

ssh pi@192.168.1.24

⚠️ linux user : to copy inside the terminal : ctrl + shift + c to paste inside the terminal : ctrl + shift + v

• Osx :

  start terminal ( 🍎 + space and search for terminal)

ssh -p 55 pi@er401.duckdns.org

• Windows :
• install putty
  • got to putty download page
    • putty will give windows ssh ability ...
• connect to:
  • server: ipadresse
  • port 22
  • user pi

---

---

create your new home

first

1. create a User

    sudo useradd <username>

2. add user to groups and privilege

• add user to admin list

    sudo usermod -a -G sudo yourUserName

• change shell to zsh ( optional )

    chsh -s /bin/zsh

• exit user pi

    exit

3. reconnect with your username and password

    ssh YOUR_USER_NAME@ADRESSEIP

4. welcome to your new home

   1. your home folder is in /home/yourUserName
      1. hint : you can check where you are with the command pwd (Print Working Directory)
   2. learm about linus folder structure -> learn more

---

DO SOME STUFF

general cli commands

navigate

• . the current directory ( folder)
• .. the parent directory
• man : view the manual of a command ( ex : man ls )
• pwd : Use the pwd command to find out the path of the current working directory (folder) you’re in
• cd : change directory to go inside a new directory
• ls : list the current directory content
• cp : to copy documents / folders
• mv: to move documents / folder
• mkdir: make directory create a folder
• touch: create an empty file
• rm : remove folder and files ⚠️ no return possible / read and think twice before smashing enter
• find: to find / search for files

system stuffs

• sudo : super user do get super privileges to do system stuff ⚠️ sudo can do ANYTHING , even destroy system
• du : disk usage ... to see .. disk usage ( use it with -h argument for human readable output )
• top and htop : to monitor system ( application / ram / cpu usage)
• killall : kill a process by name e:killall firefox will quit and kill all firefix process
• uname : view system information ( kernel / linux version ....)
• sudo reboot : restart computer ( must be sudo to execute )
• sudo halt || sudo shutdown now : shutdown computer ( must be sudo)

general help

• ctrl + r : search in history for already used commands
• ctrl + c : kill running command

---

getting started with python

==underconstruction==

just some code to try

import time
import math
x = 0
try :
    while True:
        x = x+1
        time.sleep(0.5)
        print(" la vlaeur de x est de = {}".format(x))
        if x>100:
            x=0
            
except KeyboardInterrupt:
    print('Hello user you have pressed ctrl-c button.')

create a simple chat with python

https://python.plainenglish.io/create-a-basic-lan-chat-room-with-python-f334776bf70c

fixed code

===client===

import socket
import threading

my_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

PORT = 8000
ADDRESS = "localhost" # Same as "127.0.1.1"

my_socket.connect((ADDRESS, PORT))

nickname = input("Choose your nickname : ").strip()


while not nickname:
    nickname = input("Your nickname should not be empty : ").strip()
    
    

def thread_sending():
    while True:   
        message_to_send = input("your message :")
        if message_to_send:
            message_with_nickname = nickname + " : " + message_to_send
            my_socket.send(message_with_nickname.encode())    


def thread_receiving():
    while True:
        message = my_socket.recv(1024).decode()
        print(message)


thread_send = threading.Thread(target=thread_sending)
thread_receive = threading.Thread(target=thread_receiving)


thread_send.start()
thread_receive.start()

===server===

import socket
import threading 

my_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

PORT = 8000
ADDRESS = "0.0.0.0"

broadcast_list = []


my_socket.bind((ADDRESS, PORT))


def thread_accept():
    while True:
        my_socket.listen()
        client, client_address = my_socket.accept()
        broadcast_list.append(client)
        start_listenning_thread(client)
        
def start_listenning_thread(client):
    client_thread = threading.Thread(
            target = listen_thread,
            args = (client,) #the list of argument for the function
        )
    client_thread.start()
    
def listen_thread(client):
    while True:
        message = client.recv(1024).decode()
        if message:
            print(f"Received message : {message}")
            broadcast(message)
        else:
            print(f"client has been disconnected : {client}")
            return
        
        
def broadcast(message):
    for client in broadcast_list:
        try:
            client.send(message.encode())
        except:
            broadcast_list.remove(client)
            print(f"Client removed : {client}")
            

thread_accept()

---

create folder in apache server

wft is apache :

apache is a http web server wiki page

there other solution like [https://www.lighttpd.net/]{https://www.lighttpd.net/} or the popular https://nginx.org/en/

apache is well documented and often the one you'll find on a web server service

1. create folder first with your username

    sudo mkdir -p /var/www/html/$USER 

2. change ownership to your user

    sudo chown -R $USER:$USER /var/www/html/$USER

3. make sure permissions on www are ok

    sudo chmod -R 755 /var/www

4. create your first webpage to serve

    touch /var/www/html/$USER/index.html

5. put something in it

    nano /var/www/html/$USER/index.html
    or 
    vim /var/www/html/$USER/index.html

6. content example

    <html>
       <head>
          <meta charset="UTF-8">
          <title>Welcome to my page</title>
       <style>
         h1{
         font-size : 42px;
         }
        </style>
       </head>
    <body>
          <h1> 📡 Success!! 📡 </h1>
    </body>
    </html>

mjpeg-streamer ( video server )

https://github.com/jacksonliam/mjpg-streamer

github project page

⚠️ don't follow the instructions during this class ( installation already done )

• after install

  • add your user to video group

    usermod -a -G video $USER
    

    this will give your user to access camera equipement

  • logout and back in

  • go have a look

    • start server

    cd ~/mjpg-streamer/mjpg-streamer-experimental &&  ./mjpg_streamer -o "output_http.so -w ./www" -i "input_raspicam.so"
    

  • go check

    #in a local network
    http://IP_FOR_THE_RASPBERRY_PI:8080/?action=stream
    #in that case with dyndns service ( duckdns ) and port redirection ( 666 -> 8080)
    http://er401.duckdns.org:666/?action=stream