When working with Git, it's important to keep your repository clean and organized. One way to do this is by excluding certain files, such as obj files, from being committed. Obj files are intermediate files generated during the compilation process, and they can easily clutter up your repository. Here's how you can exclude obj files from Git commit:

1. Create a .gitignore file: If you don't already have a .gitignore file in your repository, you'll need to create one. This file allows you to specify which files or patterns should be ignored by Git.

2. Open the .gitignore file: Once you have the .gitignore file in your repository, open it in a text editor.

3. Add the obj files to the .gitignore file: In the .gitignore file, you can specify which files or patterns should be ignored by Git. Simply add a line for each obj file or pattern that you want to exclude, such as '*.obj' or '*/build/*.obj'.

4. Save the .gitignore file: After adding the obj files to the .gitignore file, save the file and close the text editor.

5. Remove obj files from the repository: If you've already committed obj files to your repository, you'll need to remove them from the repository using the 'git rm' command. For example, you can use the following command to remove all obj files from the repository:

```

git rm '*.obj'

```

6. Commit the changes to the .gitignore file: After excluding obj files from the repository, you can commit the changes to the .gitignore file using the 'git commit' command.

By following these steps, you can easily exclude obj files from being committed to your Git repository. This will help keep your repository clean and optimized, making it easier to manage and collaborate with others. Remember to always review the changes in your repository before making a commit to ensure that you're not including any unwanted files.