Understanding File Editing in Vim: What Happens Under the Hood
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Chapter 1: The Basics of Vim File Editing
When you edit a file in Vim, there are several processes that take place behind the scenes. Let’s take a closer look at what occurs when you use Vim for file editing.
First, we can create a new file with the following command:
touch david.md
To observe the contents of this file in real-time, we can use:
tail -f david.md
Now, if you open a separate terminal window and add some content to the file, you can use:
echo "hahahah" > david.md
As you append more text in the second terminal, you’ll notice that the changes appear automatically in the first terminal.
Next, let’s launch the david.md file in Vim and add additional text. After saving, you might notice that the left pane does not reflect any changes. Why is that the case?
Even after exiting Vim, the left pane still shows no updates. What could be happening here?
This can be puzzling, especially when you try to append text using the traditional methods, only to find that changes aren’t showing up. What’s really going on during this Vim editing session?
The tail -f command is designed to display the end of a file and update it as new lines are added. However, how it responds can vary based on how the file is being edited.
When you use:
echo "wowowowsdfsdfsfow" >> david.md
you're appending directly to the file, which tail -f can detect and display.
In contrast, when using Vim (or many other text editors), the operation is different. Instead of appending directly, these editors typically create a temporary file that includes your changes, delete the original file, and then rename the temporary file to the original file's name. This approach enhances safety, preventing data loss in case the editor crashes during the writing process.
Since the original file is removed, tail -f loses track of it and cannot show the updates. It continues to monitor the initial file, not the new one that Vim has generated.
To ensure that tail -f can track changes made by Vim, use the -F option:
tail -F david.md
This tells tail to follow the file by name rather than by reference, allowing it to continue displaying updates even after the original file has been deleted and replaced. Now, with the -F option in effect, you can monitor the file changes seamlessly!
The first video, "Linux Essentials part 7: Editing files using Vim," delves into the fundamental aspects of using Vim for file editing, showcasing techniques and best practices.