Day-3-Vim Editor and creating links

The vim editor (Vi IMproved) is a powerful, flexible text editor commonly used in Linux and Unix systems. It’s widely used by system administrators, developers, and DevOps engineers because it's lightweight and available by default on most Unix systems.

🟩 What is Vim?

Vim stands for Vi Improved. It’s a powerful text editor available on almost all Unix-based systems (like Linux).

It's used to:

• Edit configuration files

• Write shell scripts

• View and manipulate text files

VIM EDITOR
VI   Visual display editor
VIM Visual display editor improved

This is command mode editor for files. Other editors in Linux are emacs, gedit
vi editor is most popular

It has 3 modes:
1  Command Mode
2  Insert mode (edit mode)
3  Extended command mode

Note: When you open the vim editor, it will be in the command mode by default.

In the command mode the cursor’s can be used as
h/j/k/l  to move cursor left/right/up/down

🟩 How to Open Vim?

vim filename

Examples:

vim myfile.txt

• If myfile.txt doesn’t exist, it creates a new file.

• If it exists, Vim opens it for editing.

• Step 2: Enter Insert Mode

  • Press i
    → You’ll see -- INSERT -- at the bottom.

  • Now you can type anything:

      Hello, this is a test file.
      Learning Vim is fun!
    

Step 3: Exit Insert Mode

• Press Esc
  → You’re now back in Normal Mode (no -- INSERT --).

Step 4: Save and Exit

• Type :wq
  → This saves the file and quits Vim.

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🔁 Repeat:

• i → insert

• Esc → stop typing

• :wq → save and quit

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Insert Mode:

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Command Mode:

Command Mode (continued):

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Extended Mode : (Colon Mode)
Extended Mode is used for save and quit or save without quit using “Esc” key with “:”

Summary:

• vim filename – Open a file

• i – Insert mode to start typing

• Esc – Exit insert mode

• :wq – Save and exit

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Symbolic Link

What is a Link?

A link is like a shortcut or reference to a file. It allows you to access a file from different locations without duplicating the file's content.

There are two types of Links:

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Creating a soft link:

📝 Exercise 1: Create and Explore a Soft Link

1. Create a test file:

echo "This is the original file." > original.txt

2. Create a soft link named softlink.txt:

ln -s original.txt softlink.txt

3. Check the details of the soft link:

ls -l softlink.txt

• It shows softlink.txt -> original.txt

4. Read the soft link file:

cat softlink.txt

• You see the content of the original file.

5. Delete the original file:

rm original.txt

6. Try reading the soft link again:

cat softlink.txt

• You will get an error like No such file or directory because the link is broken.

Creating a hard link:

📝 Exercise 1: Create and Explore a Hard Link

1. Create a test file:

echo "This is the original file." > original.txt

2. Create a hard link named hardlink.txt:

ln original.txt hardlink.txt

3. Check the inode numbers of both files:

ls -i original.txt hardlink.txt

• You should see the same inode number for both files.

4. Modify the hard link file:

echo "Adding a line via hard link." >> hardlink.txt

5. Check contents of the original file:

cat original.txt

• You will see the added line, because both are the same file on disk.

6. Delete the original file:

rm original.txt

7. Check the content of the hard link file:

cat hardlink.txt

• The data is still accessible since the hard link points directly to the inode.

  Summary

  • Hard links share the same data and inode; deleting one doesn't remove data until all hard links are deleted.

  • Soft links point to the filename; deleting the original file breaks the link.