Как удалить кэшированные файлы с помощью Git

Introduction

Git is a powerful version control system that helps developers manage their project's file history. Sometimes files get cached in the repository that we no longer want Git to track, but we want to keep them in our local directory. The git rm --cached command allows us to remove files from Git's tracking system while preserving them in our working directory. This tutorial will teach you how to effectively use this command to clean up your repository and optimize your workflow.

Skills Graph

Creating a Sample Git Repository

To understand how to remove cached files from Git, let's first set up a sample repository with some files. This will help us see how Git caching works in practice.

Understanding Git Caching

When you add files to Git using the git add command, Git stores these files in its index (also called the staging area). These files are now "cached" or staged, waiting to be committed to the repository. Sometimes you may want to unstage these files or remove them from Git's tracking without deleting them from your local file system.

Setting Up Our Repository

Let's create a simple Git repository to work with:

1. Open a terminal window in the LabEx VM environment
2. Navigate to the project directory:

cd ~/project

3. Create a new directory for our test repository:

mkdir git-cache-demo
cd git-cache-demo

4. Initialize a new Git repository:

git init

You should see output similar to this:

Initialized empty Git repository in /home/labex/project/git-cache-demo/.git/

5. Configure your Git user information (required for commits):

git config user.name "LabEx User"
git config user.email "[email protected]"

Now we have a fresh Git repository ready for adding files. In the next step, we'll create some files and add them to Git's tracking system, which will allow us to practice removing them from the cache later.

Adding Files to the Repository

Now that we have set up our Git repository, let's create some files and add them to Git's tracking system. This will help us understand what it means for a file to be "cached" in Git.

Creating and Adding Files

1. First, let's create a few different types of files in our repository:

## Create a text file
echo "This is a sample text file" > sample.txt

## Create a config file
echo "debug=true" > config.ini

## Create a log file (which we typically don't want to track)
echo "2023-01-01: System started" > app.log

2. Check the status of our repository:

git status

You should see output similar to this:

On branch master

No commits yet

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	app.log
	config.ini
	sample.txt

nothing added to commit but untracked files present (use "git add" to track)

This shows that we have three files that Git recognizes, but they're not being tracked yet.

3. Let's add all the files to Git's staging area (cache):

git add .

4. Check the status again:

git status

Now you should see:

On branch master

No commits yet

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)
	new file:   app.log
	new file:   config.ini
	new file:   sample.txt

Notice that Git now tells us we can use git rm --cached <file> to unstage the files. The files are now cached in Git's staging area, waiting to be committed.

5. Let's commit these files to make them part of our repository's history:

git commit -m "Initial commit with sample files"

You've now successfully added files to Git's tracking system. In the next step, we'll learn how to remove specific files from Git's cache while keeping them in our local directory.

Removing a Single File from Git's Cache

Now that we have files tracked by Git, let's learn how to remove a specific file from Git's tracking while keeping it in our local directory. This is a common need when you accidentally commit files that should be excluded, such as log files, temporary files, or files with sensitive information.

Why Remove Files from Git's Cache

There are several reasons you might want to remove a file from Git's cache:

1. You accidentally added a file containing sensitive information
2. You want to exclude large binary files like logs or compiled files
3. You're setting up a .gitignore file and need to remove already-tracked files

Removing app.log from Git's Tracking

Let's imagine that we've realized the app.log file should not be tracked by Git:

1. First, let's verify that Git is currently tracking the file:

git ls-files

You should see all three files listed:

app.log
config.ini
sample.txt

2. Now, let's remove app.log from Git's tracking system while keeping it in our local directory:

git rm --cached app.log

You'll see a confirmation message:

rm 'app.log'

3. Check the status again:

git status

You'll see that app.log is now listed as an untracked file:

On branch master
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	deleted:    app.log

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	app.log

This means Git will stop tracking the file in the next commit, but the file still exists in your local directory.

4. Let's verify the file still exists in our working directory:

ls -la

You should see that app.log is still there.

5. Commit this change to finalize removing the file from Git's tracking:

git commit -m "Remove app.log from Git tracking"

6. Verify that Git is no longer tracking the file:

git ls-files

Now you should only see:

config.ini
sample.txt

But the app.log file still exists in your local directory:

cat app.log

Output:

2023-01-01: System started

Congratulations! You've successfully removed a file from Git's cache while keeping it in your local directory. In the next step, we'll learn how to handle multiple files and improve our workflow with .gitignore.

Working with Multiple Files and Directories

Now that we know how to remove a single file from Git's cache, let's explore more complex scenarios like removing multiple files or entire directories.

Creating More Files for Practice

Let's first create a few more files and a directory structure to practice with:

1. Create a directory and some additional files:

## Create a directory for temporary files
mkdir temp

## Create some files in the temp directory
echo "This is a temporary file" > temp/temp1.txt
echo "Another temporary file" > temp/temp2.txt

## Create another log file in the main directory
echo "2023-01-02: System updated" > system.log

2. Add these new files to Git's tracking:

git add .

3. Commit the changes:

git commit -m "Add temporary files and system log"

4. Verify that Git is tracking all files:

git ls-files

You should see:

config.ini
sample.txt
system.log
temp/temp1.txt
temp/temp2.txt

Removing Multiple Files from Git's Cache

Now let's say we want to remove all log files and the entire temp directory from Git's tracking.

1. Remove the log file from Git's tracking:

git rm --cached system.log

2. Remove all files in the temp directory recursively:

git rm --cached -r temp/

The -r flag is important here as it tells Git to recursively remove all files in the directory from its cache.

3. Check the status:

git status

You'll see that both the log file and all files in the temp directory are staged for deletion from Git's tracking system:

On branch master
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	deleted:    system.log
	deleted:    temp/temp1.txt
	deleted:    temp/temp2.txt

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	app.log
	system.log
	temp/

4. Commit these changes:

git commit -m "Remove logs and temp directory from Git tracking"

5. Verify that Git is no longer tracking these files:

git ls-files

Now you should only see:

config.ini
sample.txt

However, all files still exist in your local directory:

ls -la
ls -la temp/

Using .gitignore to Prevent Tracking Unwanted Files

Now that we've removed the files from Git's tracking, let's set up a .gitignore file to prevent them from being accidentally added again:

1. Create a .gitignore file:

nano .gitignore

2. Add the following patterns to the file:

## Ignore log files
*.log

## Ignore temp directory
temp/

3. Save and exit (press Ctrl+X, then Y, then Enter)

4. Add and commit the .gitignore file:

git add .gitignore
git commit -m "Add .gitignore file"

Now, even if you try to add all files to Git, it will respect your .gitignore file and not track the specified patterns:

git add .
git status

You should see that the log files and temp directory are not being added to Git's tracking.

You've now learned how to remove multiple files and directories from Git's cache and how to prevent specific files from being tracked in the future using a .gitignore file.

Advanced Techniques and Best Practices

Now that you understand the basics of removing files from Git's cache, let's explore some advanced techniques and best practices to improve your workflow.

Removing and Ignoring Files in One Step

If you have files that are already tracked by Git and you want to both remove them from tracking and add them to your .gitignore file, you can use this efficient approach:

1. Let's create a new file type we want to ignore:

## Create a build directory with some compiled files
mkdir build
echo "Compiled binary data" > build/app.bin
echo "Configuration for build" > build/build.conf

2. Add these files to Git:

git add build/
git commit -m "Add build files temporarily"

3. Now let's remove them from Git's tracking and update our .gitignore file in one workflow:

## First, edit the .gitignore file to add the build directory
echo "## Ignore build directory" >> .gitignore
echo "build/" >> .gitignore

## Now remove the tracked files from Git's cache
git rm --cached -r build/

## Commit both changes together
git add .gitignore
git commit -m "Remove build directory from tracking and add to .gitignore"

4. Verify the files are no longer tracked but still exist locally:

git ls-files
ls -la build/

Handling Sensitive Information

If you accidentally committed a file with sensitive information like passwords or API keys, removing it from Git's cache is only the first step. Git maintains a history of all commits, so the sensitive information still exists in your repository's history.

For sensitive information, you would need to:

1. Remove the file from Git's cache as we've learned
2. Change any compromised passwords or keys
3. Consider using tools like git filter-branch or BFG Repo-Cleaner to remove the sensitive data from history

This is beyond the scope of this tutorial, but it's important to be aware of this limitation.

Best Practices for Git Cache Management

Here are some best practices to follow:

1. Create a good .gitignore file early in your project: This prevents accidentally tracking unwanted files.

2. Use global .gitignore files for common patterns: You can set up a global .gitignore file that applies to all your repositories:

git config --global core.excludesfile ~/.gitignore_global

3. Be careful with git add .: This command adds all untracked files. Use more specific commands like git add <file> when possible.

4. Review changes before committing: Always use git status and git diff --cached to review what you're about to commit.

5. Use aliases for common operations: For example, you could set up an alias for removing cached files:

git config --global alias.uncache 'rm --cached'

Then you could use:

git uncache <file>

With these techniques and best practices, you now have a comprehensive understanding of how to manage Git's cache effectively to maintain a clean and efficient repository.

Summary

In this tutorial, you learned how to effectively use the git rm --cached command to remove files from Git's tracking system while keeping them in your local directory. Here's what you accomplished:

1. Set up a Git repository and learned about the concept of Git caching
2. Added files to Git's tracking system
3. Removed individual files from Git's cache using git rm --cached
4. Managed multiple files and directories with the recursive option (-r)
5. Used .gitignore to prevent unwanted files from being tracked
6. Explored advanced techniques and best practices for managing Git's cache

These skills will help you maintain a clean and efficient Git repository, prevent tracking unwanted files, and protect sensitive information. By properly managing which files Git tracks, you can focus on the important code and configuration files while ignoring temporary files, logs, and build artifacts.

Remember that removing files from Git's cache doesn't delete them from your local file system—it simply tells Git to stop tracking them. This is a powerful tool for managing your repository's contents and ensuring that only the necessary files are included in your project's history.