Day 3 Task: Basic Linux Commands

This is #90DaysofDevops challenge under the guidance of Shubham Londhe sir.

Day 3 TASK

Are you ready to dive into the world of Linux commands? Let's explore some fundamental commands that every Linux user should know.

Viewing the Contents of a File: To see what's written in a file, you can use the cat command. For example:
```
 cat filename.txt
```
Changing File Access Permissions: To modify the access permissions of files, you can use the chmod command. For instance:
```
 chmod 700 filename
```
- The first digit (7) indicates that the owner of the file (supriya.txt) has full permissions, meaning they can read, write, and execute the file.
- The second digit (0) indicates that the group owner of the file does not have any permissions.
- The third digit (0) indicates that other users (not the owner or in the group) also do not have any permissions.
- So, in simple terms, the command chmod 700 supriya.txt grants the owner of the file supriya.txt full control over the file, while denying any access to the group owner and other users.
- This ensures that only the owner has the ability to read from, write to, and execute the supriya.txt file.

Checking Command History: To review the commands you've executed previously, simply type:
```
 history
```
Removing a Directory/Folder: To delete a directory, use the rmdir command. Be cautious, as it removes empty directories.
```
 rmdir directory_name
```
Creating and Viewing a File: To create a file named fruits.txt and view its content, execute:
```
 touch fruits.txt
 cat fruits.txt
```
Adding Content to a File: To add content to the devops.txt file, one item per line, you can use a text editor like nano or simply append with echo:
```
 echo -e "Apple\nMango\nBanana\nCherry\nKiwi\nOrange\nGuava" > devops.txt
```
Displaying Top Three Fruits: To display only the top three fruits from the file, you can use the head command:
```
 head -n 3 devops.txt
```
Showing Bottom Three Fruits: To show only the bottom three fruits from the file, utilize the tail command:
```
 tail -n 3 devops.txt
```
Creating and Viewing Another File: Create a file named Colors.txt and view its content:
```
 touch Colors.txt
 cat Colors.txt
```

Adding Content to Colors.txt: Add colors to the Colors.txt file, one per line:

echo -e "Red\nPink\nWhite\nBlack\nBlue\nOrange\nPurple\nGrey" > Colors.txt

Finding Differences Between Files: To identify the differences between fruits.txt and Colors.txt, use the diff command:
```
diff fruits.txt Colors.txt
```