The terminal isn’t just a simple terminal; it’s more like a terminal emulator. It’s a physical tool, much like a keyboard or monitor, used for interacting with the Shell through commands. The Shell is the user interface we use to communicate with the Linux operating system’s core, known as the Linux kernel. There are various shells available, such as bash and zsh.
You can identify which shell you’re using by executing the following command:
ps
Mastering the Art of Linux Commands:
Now, let’s say you’re not so great at remembering all those complex commands. When you need assistance with any command, you can consult the manual by using the “man” command. For example:
if you’re unsure about how the “ls” command works, type:
man ls
Now, imagine you’re typing a command, like “Uname,” and you forget how it works. To get help with that specific command, you can use:
uname --help
The Secret Weapon: “Apropos”
Sometimes, you may not even know which command to use for a specific task. In such cases, there’s a secret weapon – the “apropos” command. It helps you find the right command based on your intent.
For instance, if you need to discover what devices are connected to your computer through USB but can’t recall the command, try this:
apropos usb
Similarly, if you’re on a quest to find the perfect command for compressing a file, simply enter:
apropos compress
In simple terms, the terminal is like a communication tool that lets you talk to your computer’s core. If you forget a command or need help finding the right one, just use “man” or “apropos” to get the information you need. It’s like having a handy guide to navigate your way through Linux.
You will need to install Python 3 locally on your Laptop.
Debian/Ubuntu/Mint: In the terminal, run
sudo apt-get install python3
After Installation make sure python3 is installed successfully, by checking the version
python3 --version
Nmap Network testing tooling
You’ll also need to install ncat, which is part of the Nmap network testing toolkit. We’ll be using ncat to investigate how web servers and browsers talk to each other.
Debian/Ubuntu/Mint: In the terminal, run
sudo apt-get install nmap
sudo apt-get install ncat
To check whether ncat is installed and working, open up two terminals. In one of them, run
ncat -l 9999
in the other,
ncat localhost 9999
Then type something into each terminal and press Enter. You should see the message on the opposite terminal.
What is a Server
A server is just a program that accepts connections from other programs on the network.
When you start a server program, it waits for clients to connect to it. server waiting for your web browser to ask it for a page. Then when a connection comes in, the server runs a piece of code like calling a function to handle each incoming connection. A connection in this sense is like a phone call, it’s a channel through which the client and server can talk to each other. Web clients send requests over these connections, and servers send responses back.
a web server provides support for HTTP (Hypertext Transfer Protocol). As its name implies, HTTP specifies how to transfer hypertext (linked web documents) between two computers.
Running the first web server
So, let’s get started with the demo web server:
Open up a terminal.
cd into a directory that has some files in it ( text files, HTML files, or images ).
Run python3 -m http.server 8000 in your terminal.
Look! The server tells me that it’s serving HTTP on port 8000.
When you start up the demo server, it will print a message telling you that it’s serving HTTP. Leave it running, and leave the terminal open. Now try accessing http://localhost:8000/ from your browser. You should see something like this
In my web browser, I see the demo server showing the same files that are in my Documents directory.
And that’s the Python demo web server, running on your own computer. It serves up files on your local disk so you can look at them in your browser.
When you put localhost:8000 in your browser, your browser sends an HTTP request to the Python program you’re running. That program responds with a piece of data, which your browser presents to you.
Look in the terminal where you ran the demo server. You’ll see a server log with an entry for each request your browser sent.
Hostnames
HTTPS URI includes the hostname of the web server, like www.google.com or www.cheeseboardcollective.coop
A hostname in a URI can also be an IP address: for example, if you put http://216.58.194.174/ in your browser, you’ll end up at Google.
The Internet tells computers apart by their IP addresses; every piece of network traffic on the Internet is labeled with the IP addresses of the sending and receiving computers. In order to connect to a web server such as www.google.com, a client needs to translate the hostname into an IP address. Your operating system’s network configuration uses the Domain Name Service (DNS) a set of servers maintained by Internet Service Providers (ISPs) and other network users to look up hostnames and get back IP addresses.
In the terminal, you can use the host program to look up hostnames in DNS:
The output shows both an IPv4 address and an IPv6 address.
Another similar command called nslookup
This command also displays the IP address for the hostname you give it; but it also shows the IP address of the DNS server that’s giving it the answer
Send a Request
use ncat to connect to the demo server and send it an HTTP request.
Use ncat 127.0.0.1 8000 to connect your terminal to the demo server.
Then type these two lines:
GET / HTTP/1.1
Host: localhost
After the second line, press Enter twice. As soon as you do, the response from the server will be displayed a lot of text on your terminal.
Everything after the line Host: localhost is part of the server’s response.
Be a web server!
Use ncat -l 9999 to listen on port 9999. Connect to it with your web browser at http://localhost:9999/.
and see the response from the server in your terminal
Next, send an HTTP response to your browser by typing it into the terminal, right under where you see the headers the browser sent to you.
HTTP/1.1 307 Temporary Redirect
Location: https://www.eff.org/
At the end, press Enter twice to send a blank line to mark the end of headers.
Docker is a Linux-based, open-source platform that developers use to build, run, and package applications for deployment using containers.
Containers:
Unlike virtual machine, Docker containers offer:
Allow running multiple applications in Isolation
Faster application execution
Lightweight( no need of full-blown Operating system)
Need less hardware resources
Use OS of the host
Docker containers essentially modularize the functionality of your application into multiple components that can be deployed, tested, or scaled independently as needed.
IMAGES:
Images contain instructions for creating a Docker container. Images define:
Application dependencies
The processes that should run when the application launches
You can get images from DockerHub or create your own images by including specific instructions within a file called Dockerfile
Docker Engine:
Docker Engine is the core component of a Docker architecture on which the application runs. Docker Engine as the application that’s installed on the system that manages containers, images, and builds.
A Docker Engine uses a client-server architecture
Installing docker on Ubuntu
———————————————————————————————————————
Update the “apt” package index.
sudo apt update
To install docker type the following command in your terminal.
sudo apt install docker.io
Then start the docker services using command
sudo systemctl start docker
To download/pull the image for docker run the following command
docker pull hello-docker
check the downloaded images using command
docker image ls
we will run our hello-docker image using following command
JavaScript is an open source and cross-platform language and therefore mostly used for creating network-centric applications. JavaScript is used in web technologies to make web pages interactive. Along with HTML and CSS, JavaScript is widely used in web servers and databases.
Why to learn JavaScript?
It is client-side/browser programming language.
Build very interactive user interfaces with frameworks.
Interpreted (no need of compilers)
It is most popular & loved language around the globe.
Used to build client-side applications, also with the help of its frameworks namely Node.js and Express.js, it is now widely used to build server-side applications too.
VS code or any simple editor you can use to start Javascript.
let’s move to Javascript code.
Print hello world! in JavaScript
console.log("hello world!");
JavaScript console API
console.log("Hello World" , 4+6, "from Waqar");
console.warn("this is warning");
console.error("this is an error");
Variables in JavaScript
var number1 = 3.8;
var number2 = 2.2;
console.log(number1 + number2);
Data types in JavaScript
//strings
var str1 = "This is Waqar";
var str2 = "This is also Waqar";
console.log(str1)
//numbers
var num1 = 455;
var num2 = 34.21;
//objects
var marks = {
Waqar: 97,
Kashif: 98.32,
kausar: 80
}
console.log(marks)
//Booleans
var a = true;
var b = false;
console.log(a,b);
var und; //here we just declare a variable there is nothing stored in und so it in undefined
console.log(und);
var n = null;
console.log(n); //null stored in var n
Operators in JavaScript
//Arithmatic operators
var s = 100
var t = 10
console.log("The value of s + t is " ,s+t );
console.log("The value of s - t is " ,s-t );
console.log("The value of s * t is " ,s*t );
console.log("The value of s / t is " ,s/t );
//Assignment operators
var c = s
c += 5;
console.log(c);
//Comparison operators
var x = 34
var y = 30
console.log(x>= y);
console.log(x<= y);
console.log(x == y);
// Logical operators (AND)
console.log(true && true)
console.log(true && false)
console.log(false && true)
console.log(false && false)
// Logical operators (OR)
console.log(true || true)
console.log(true || false)
console.log(false || true)
console.log(false || false)
// Logical not !
console.log(!false)
console.log(!true)
Function in JavaScript
function avg(a , b)
{
return (a+b)/2;
}
//DRY = do not repeat yourself
c1 = avg(4,6);
c2 = avg(14,16);
console.log(c1, c2);
Conditional statementsin JavaScript
//Single statement
var age = 10;
if(age > 18)
{
console.log("You are Eligible");
}
//if-else statements
if(age > 18)
{
console.log("You are Eligible");
}
else{
console.log("You are not Eligible");
}
//if-else ladder
var marks = 90;
if(marks >= 86)
{
console.log("A+");
}
else if(marks > 78)
{
console.log("A-");
}
else if(marks > 70)
{
console.log("B+");
}
else if(marks > 50)
{
console.log("pass");
}
else{
console.log("F");
}
Arrays & it’s methods in JavaScript
let myArr = ["Fan" , true , null, 444];
console.log(myArr.length);
(myArr.pop()); //pop will delete last item from array
console.log(myArr);
myArr.push("waqar"); //it will add item into array
console.log(myArr);
myArr.shift(); //draw the first element
console.log(myArr);
const newLen = myArr.unshift("Ahmed"); //unshift will add item at start of Array
console.log(newLen);
console.log(myArr);
//string methods in JAVASCRIPT
let mystring = "Waqar is good boy, Yes good boy";
console.log(mystring.length);
console.log(mystring.indexOf("Waqar")); //Indexof will return index of string from start
console.log(mystring.lastIndexOf("Yes")); // lastIndexof will return index of string from last
console.log(mystring.slice(0,3));
console.log(mystring.replace("Waqar" , "Ahmed"));
Iteration (Loops) in JavaScript
var array = [1,2,3,4,5];
for(let i =0; i<array.length; i++)
{
console.log(array[i]);
}
let j = 0;
while(j<array.length)
{
console.log(array[j]);
j++;
}
do{
console.log(array[j]);
j++;
}while(j<array.length)
//break and continue statements
let arr1 = [1,2,3,4,5];
for(let i =0; i<array.length; i++)
{
if(i == 2)
break;
console.log(array[i]);
}
for(let i =0; i<array.length; i++)
{
if(i == 2)
continue;
console.log(array[i]);
}
Date and time in JavaScript
myDate = new Date();
console.log(myDate);
console.log(myDate.getTime()); //getTime will return time in seconds
console.log(myDate.getDay()); //getDay will return number from monday to that day
console.log(myDate.getFullYear()); //getFullYear will return years
console.log(myDate.getMinutes()); //getMinutes will return minutes currently
JavaScript DOM Manipulation
//DOM document object model (in any page links , images, names) are DOM
//we have some Dom methods with the help of these methods we can manipulate the HTML as Dyanamacilly by JAVASCRIPT
// //DOM manipulation
let elem = document.getElementById('click');
console.log(elem);
let elemClass = document.getElementsByClassName('container');
console.log(elemClass);
elemClass[1].style.background = 'red';
elemClass[1].classList.add('bg-primary'); //adding class to another class
elemClass[1].classList.add('text-success');
console.log(elemClass[0].innerHTML)
console.log(elemClass[0].innerText)
tn = document.getElementsByTagName('div');
console.log(tn);
Events in JavsScript
function clicked()
{
console.log("The button was clicked");
}
window.onload = function()
{
console.log("The document was loaded");
}
//once our document loaded we can perform some operations
//here we work on first container
firstcontainer = addEventListener("click" , function(){ //it will be print on first container
document.querySelectorAll('.container')[1].innerHTML = "<b> We have clicked </b>"
console.log("click hua")
})
firstcontainer = addEventListener("mouseover" , function(){
console.log("Mouse on container");
})
firstcontainer = addEventListener("mouseout" , function(){
console.log("Mouse out of container");
})
let prevHTML = document.querySelectorAll('.container')[1].innerHTML;
firstcontainer = addEventListener("mouseup" , function(){
document.querySelectorAll('.container')[1].innerHTML = prevHTML;
console.log("Mouse up on container");
})
firstcontainer = addEventListener("mousedown" , function(){ //when you will click
document.querySelectorAll('.container')[1].innerHTML = "<b> We have clicked </b>"
console.log("Mouse down on container");
})
Arrow function in JavaScript
function summ(a,b){
return a+b;
}
summ = (a,b)=>{ //we can write function by arrow which is same as normal fun but it will help when we have need a function between code.
return a+b;
}
logkaro = ()=>{
document.querySelectorAll('.container')[1].innerHTML = "<b> set interval fired</b>"
console.log("I am your log")
}
setTimeout and setInterval in JavsScript
setTimeout(logkaro , 2000);
clr = setInterval(logkaro , 2000);
//use clearInterval(clr)/clearTimeout(clr) to cancel setInterval and setTimeout
In this blog, You will learn how to Install 32-bit masm. MASM (Microsoft macro assembler ) is a compiler that is used to compile the Assembly code to your machine.
If you are using Ubuntu or any Debian Linux OS then first you need to download** Virtualbox **and install **Windows OS **on it.
First, you need to go to your browser and download **MASM **you can go to the following link https://www.masm32.com/
Click on download
After that click on Western Europe
Now Click on Download Dos MASM32 ….(4.72mb)
Once it is downloaded to download and extract there. Then double click on the install it will start the installation. This will ask for many permission just click OK.
This will take some time. Once done, it will open the Welcome file. When you see that it means that the masm has been successfully installed.
HELLO WORLD IN ASSEMBLY LANGUAGE
Now open the masm and copy this code into it. This code will produce Hello World.
.
386 .model flat, stdcall option casemap:none
include \masm32\include\windows.inc include \masm32\include\kernel32.inc includelib \masm32\lib\kernel32.lib include \masm32\include\user32.inc includelib \masm32\lib\user32.lib
.
data
msg db "Hello world!!!", 0 cpt db "MY FIRST PROGRAM!!!", 0
Save this file in the directory where you have masm installed. Put this file in the masm32 folder.
Then open masm and click on option project and then click on build all. Then it will Build and compile our code.
Then you will open **CMD **in the directory in which u saved your **.asm file **and then you simply type your filename without .asm and then hit enter and you are done! You can see the output
So, that’s it for this web journal. Trust you appreciate it. Do let me know about your criticism within the comment segment. I will truly appreciate it.
Waqar 