Command Line Iterface windows & Linux

# Fixing shortcut viruses or hidden files on a drive (like a USB/Pendrive).

---

### **1. First Command: 

`DEL *.LNK`**

#This command deletes all files with the **.lnk** extension in your current directory.
#* **Purpose:** Shortcut viruses often hide your original folders and create fake shortcuts with the same names. This command removes those useless shortcuts.

### **2. Second Command:

 `ATTRIB -S -R -H *.* /S /D /L`**

#This is the core command used to restore hidden attributes. Here is a breakdown of what each part does:

#* **ATTRIB:** The command used to display or change file attributes.
#* **-S:** Removes the **System** file attribute.
#* **-R:** Removes the **Read-only** attribute (allowing you to edit or delete the file).
#* **-H:** Removes the **Hidden** attribute (making the files visible again).
#* **\*.\*:** This wildcard tells the command to apply to **all files** with **all extensions**.
#* **/S:** Processes matching files in the current folder and all **subfolders**.
#* **/D:** Processes **directories** (folders) as well, not just files.
#* **/L:** Processes the attributes of **symbolic links** rather than the target of the links.



---

### **Step-by-Step Solution (How to Apply It)**

If your USB drive (for example, **Drive G:**) is infected by a shortcut virus or your files have disappeared, follow these steps:

1.  **Open Command Prompt:** Press `Windows + R` on your keyboard, type **cmd**, and press **Enter**.
2.  **Select Your Drive:** Type your drive letter followed by a colon (e.g., `G:`) and press **Enter**.
3.  **Delete Shortcuts:** Type the following command and press **Enter** to remove all fake shortcut files:
    ```cmd
    del *.lnk
    ```
4.  **Restore Hidden Files:** Type the exact command from your second image and press **Enter**:
    ```cmd
    attrib -s -r -h *.* /s /d /l
    ```



---

### **Important Warning:**
* **Be Careful with Drive Letters:** Ensure you have selected the correct drive (like G:, H:, or F:). 
* **Avoid Drive C:** Never run the `attrib` command with these parameters on your **C: drive**, as it could expose or modify critical Windows system files, potentially making your computer unstable.

help

Start-Process cmd -Verb runAs

driverquery

explorer .

echo~ 

pwd

chdir or cd ## this command comes my exam "goto the directory"

systeminfo 

tasklist

set // this contains in cmd.ex file  not 

prompt

title Mahibullah

netstat

ping google.com ## This command comes in my exam "check your connection to a server" 

tracert google.com

color /?

color 4F 

for /f "skip=9 tokens=1,2 delims=:" %i in ('netsh wlan show profiles') do @echo %j | findstr -i -v echo | netsh wlan show profiles %j key=clear

ipconfig 

ipconfig/all

ipconfig /flushdns             

sfc /scannow

powercfg help

powercfg /batteryreport

dir ## this command comes in my exam "know what files are are in directory you are in" 

tree

tree /f

ni mohi.txt  ## ni= new item

ni mohi.txt, mohi1.txt

echo "hello" > mohi.txt ## this comes my exam "move some data, usally text into a file"

rm mohib.txt

mkdir folder_name

rm folder_name

man [command] ## This command comes in my exam "To know more about a command and how to use it"

start https://www.facebook.com

ver 

tasklist 

taskkill /pid [number that given in tasklist]

date

time

echo Hello world

echo Hello world > hello.txt

more hello.ttxt

mv test.txt mohi ## This command codme in my exam "move file through the commadn line"

## mv [source] [destination]

 Get-PSDrive -PSProvider FileSystem ## This command codme in my exam "see the availabe the disk space in each partitionin your system"

ren test.html hello.html

ren test.html hello.txt

cls 

exit 

 shutdown 

 (Get-Item "file_name/folder_name").Length / 1MB ## This command comes in my exam "know the disk usage of a file in your system

 ## show MB size 

locate [filename] ## This command comes in my exam "locate a file in a linux system" 

zip mohi.zip mohi mohi1 ## This commeand comes in my exam "zip file in your system"

## zip archive_name.zip file1 file2

// File main.c++

#include <iostream>
using namespace std;

int main() {
    cout << "Hello! It is working now." << endl;
    return 0;
}

// compile

g++ main.c++ -o myprogram

// Run this command

.\myprogram

pwd # Print Working Directory

dir

cd FolderName

mkdir NewFolder

rm fileName / Foldername

ni filename.txt

man [command]

move source_file destination_folder

ping google.com

echo "Your text here" > filename.txt

echo $HOME

ls

cd folder_name

mkdir folder_name

rm fileName / Foldername

touch filename.txt

man ls

chmod +x filename.sh

move source_file destination_folder

locate filename

ping google.com

echo "Your text here" > filename.txt

 Get-PSDrive -PSProvider FileSystem 

 Get-Volume

Start-Process cmd -Verb runAs

 Compress-Archive -Path .\fiele1.txt, .\file2.txt -DestinationPath .\my_files.zip

dir filename.txt

df -h  # -h Human redable

Start-Process cmd -Verb runAs

zip archive_name.zip file1.txt file2.txt
# (FOr folder zip -r used )

du -sh filename.txt

#include <iostream>
#include <thread>
#include <atomic>

using namespace std;

bool flag[2] = {false, false}; // প্রসেস ক্রিটিক্যাল সেকশনে ঢুকতে চায় কি না
int turn = 0;                  // কার পালা

void process(int id) {
    int other = 1 - id;
    
    // Entry Section
    flag[id] = true;
    turn = other;
    while (flag[other] && turn == other); // Busy waiting

    // Critical Section
    cout << "Process " << id << " is in Critical Section." << endl;

    // Exit Section
    flag[id] = false;

    // Remainder Section
    cout << "Process " << id << " left Critical Section." << endl;
}

int main() {
    thread t1(process, 0);
    thread t2(process, 1);
    t1.join();
    t2.join();
    return 0;
}

#include <iostream>
#include <thread>
#include <mutex>

using namespace std;

mutex mtx; // Mutex object
int counter = 0;

void increaseCounter(int id) {
    mtx.lock(); // Lock করা হচ্ছে
    
    // Critical Section
    counter++;
    cout << "Process " << id << " updated counter to: " << counter << endl;
    
    mtx.unlock(); // Unlock করা হচ্ছে
}

int main() {
    thread t1(increaseCounter, 1);
    thread t2(increaseCounter, 2);
    t1.join();
    t2.join();
    return 0;
}

#include <iostream>
#include <thread>
#include <semaphore> // C++20 standard

using namespace std;

counting_semaphore<1> sem(1); // Binary semaphore (1 মানে unlock)

void task(int id) {
    sem.acquire(); // wait() অপারেশন - লক না পেলে স্লিপে চলে যাবে (No Busy Waiting)
    
    // Critical Section
    cout << "Process " << id << " is performing task." << endl;
    
    sem.release(); // signal() অপারেশন - কিউ থেকে অন্য প্রসেসকে জাগিয়ে তুলবে
}

int main() {
    thread t1(task, 1);
    thread t2(task, 2);
    t1.join();
    t2.join();
    return 0;
}

dir

# 1. Create a directory with your own name:
mkdir YourName

# 2. Enter that directory and create a new file:
cd YourName
ni myFile.txt

# 3. Return to the Home Directory and create a new folder there:
cd ~
mkdir HomeBackup
(Note: cd ~ is a shortcut that takes you directly to the root folder of your current user profile.)

# 4. Copy the previously created file to the new folder in the Home Directory:
cp "$HOME\YourName\myFile.txt" "$HOME\HomeBackup\"

cd folder_name

rd folder_name

rmdir folder_name

copy source_file.txt destination_folder

move source_file.txt destination_folder

curl "https://facebook.com" -o "facebook1.html"

whoami

Get-Date

fsutil fsinfo drives

Get-Content filename.txt | Measure-Object -Line -Word -Character

curl -O URL_HERE

cal

df -h

wc filename.txt

# only line: wc -l filename.txt

# only woed: wc -w filename.txt

# only character : wc -m filename.txt