Introduction

During the use of Linux, we often need to edit configuration files, write scripts, or modify log files. The most commonly used, classic, and also the most “love-hate” tool for beginners is the Vim editor.

Vim is one of the most important text editors in the Linux world. It is lightweight, powerful, and almost universally available across all systems. In this chapter, we will systematically introduce it from three aspects:

1. Basic concepts of text editors
2. The three modes of Vim
3. Common commands and operations in Vim

1. Basic Concepts of Text Editors

In Linux, the vast majority of configuration files and code are plain text files. Therefore, mastering an efficient text editor is almost an essential skill.

Common text editors in the Linux environment include:

Editor	Features
<span>nano</span>	Simple and easy to use, suitable for beginners (few commands, limited functionality)
<span>vi</span>	Early Unix built-in editor, lightweight but not easy to master
<span>vim</span>	“Vi IMproved” – an enhanced version of vi, powerful, supports syntax highlighting, plugins, and multi-mode editing
<span>gedit</span>	Graphical editor, similar to Notepad
<span>emacs</span>	Highly customizable editor, extremely powerful, but with a steep learning curve

Tip: Vim has become the “default editor” in Linux server environments. When you execute commands like <span>crontab -e</span> or <span>git commit</span>, Vim is what opens!

Practical Case: Opening a Configuration File

Suppose we want to modify the system’s network configuration file <span>/etc/hosts</span>:

sudo vim /etc/hosts      # Use vim to open the hosts file

After opening, you may be surprised to find that keyboard input is ineffective, the arrow keys are jumping around, and nothing seems to respond.

Don’t panic – this is not a system freeze, but because you haven’t yet understood the three modes of Vim.

2. The Three Modes of Vim

The most unique design of Vim is its multi-mode editing. The meaning of key presses is completely different in different modes. Understanding mode switching is key to learning Vim.

Mode	Function Description	How to Enter	How to Exit
Command Mode	The default mode, used for moving the cursor, deleting, copying, pasting, etc.	Default entry upon starting vim	Press <span>i</span>, <span>a</span>, or <span>o</span> to enter Insert Mode
Insert Mode	Allows normal text input	Press <span>i</span>, <span>a</span>, or <span>o</span> in Command Mode	Press <span>Esc</span> to return to Command Mode
Last Line Mode	Used for saving, exiting, searching, replacing, etc.	Enter <span>:</span> in Command Mode	Automatically returns to Command Mode after executing the command

Practical Case: Editing and Saving a File

Let’s go through the steps to experience Vim’s “multi-mode logic”:

vim test.txt          # Open or create a text file
i                     # Enter Insert Mode (can input text)
Hello Linux!          # Input content
Esc                   # Return to Command Mode
:wq                   # Save and exit the file

Explanation:

• i: Enter Insert Mode
• Esc: Return to Command Mode
• :wq: Save (write) and exit (quit)

If you only want to save without exiting, use :w

If you want to exit without saving, use :q!

3. Common Commands and Keys in Vim

Familiarity with common commands is key to moving from “being able to use Vim” to “mastering Vim”.

1️⃣ File Operation Commands

Command	Function
<span>:w</span>	Save the file
<span>:q</span>	Exit Vim
<span>:wq</span>	Save and exit
<span>:q!</span>	Force exit without saving
<span>:w new.txt</span>	Save as a new file
<span>:e filename</span>	Open a new file
<span>:r filename</span>	Read the contents of another file into the current cursor position

2️⃣ Cursor Movement Commands

Command	Function
<span>h / l</span>	Move left / right
<span>j / k</span>	Move down / up
<span>0</span>	Move to the beginning of the line
<span>$</span>	Move to the end of the line
<span>gg</span>	Jump to the beginning of the file
<span>G</span>	Jump to the end of the file
<span>/keyword</span>	Search for a keyword
<span>n / N</span>	Repeat search down / up

3️⃣ Text Editing Commands

Command	Function
<span>x</span>	Delete the character under the cursor
<span>dd</span>	Delete the entire line
<span>yy</span>	Copy the entire line
<span>p</span>	Paste below the cursor
<span>u</span>	Undo the last operation
<span>Ctrl + r</span>	Redo (restore)
<span>:set number</span>	Show line numbers
<span>:set nonumber</span>	Turn off line numbers

Practical Case: Quickly Modifying a Configuration File

Suppose we want to modify a configuration in <span>/etc/ssh/sshd_config</span>:

sudo vim /etc/ssh/sshd_config   # Open the SSH configuration file
/Port                           # Search for the keyword "Port"
n                               # Jump to the next match
i                               # Enter Insert Mode
# Modify the port number (e.g., change to 2222)
Esc                             # Return to Command Mode
:wq                             # Save and exit

Explanation:

<span>/Port</span>: Find the configuration item

<span>n</span>: Continue searching for the next

<span>i</span>: Modify content

<span>:wq</span>: Save changes

With these steps, you have completed a secure modification of the SSH configuration file!

Conclusion

Vim may seem complex, but its logic is very clear – left hand for commands, right hand for thinking; once mastered, you will never want to part with it.