In the world of software development, particularly when using Git for version control, it is often necessary to determine which files have been changed in a specific commit. This information is crucial for code reviews, debugging, and deployment processes. The git diff-tree command is a powerful tool that can be used to list the files that have been modified in a commit. This article will guide you through the process of using git diff-tree with the --no-commit-id, --name-only, and -r options to achieve this on a Linux system.

Examples:

1. Basic Usage:

To list the files changed in a specific commit, you can use the following command:

   git diff-tree --no-commit-id --name-only -r <commit-sha>

Replace <commit-sha> with the SHA-1 hash of the commit you are interested in. For example:

   git diff-tree --no-commit-id --name-only -r 1a2b3c4d5e6f7g8h9i0j

2. Using in a CI/CD Pipeline:

In a Continuous Integration/Continuous Deployment (CI/CD) pipeline, you might want to automate this process. Assuming you are using GitLab CI, you can use the predefined environment variable $CI_COMMIT_SHA to get the commit SHA of the current build. Here is a sample script that can be added to your .gitlab-ci.yml file:

   stages:

     - check_changes



   check_changes:

     stage: check_changes

     script:

       - git diff-tree --no-commit-id --name-only -r $CI_COMMIT_SHA

3. Filtering by File Type:

If you are only interested in changes to specific types of files, you can pipe the output to grep. For example, to list only JavaScript files:

   git diff-tree --no-commit-id --name-only -r $CI_COMMIT_SHA | grep '\.js$'

4. Storing the Output:

You may want to store the list of changed files in a text file for further processing. This can be done by redirecting the output:

   git diff-tree --no-commit-id --name-only -r $CI_COMMIT_SHA > changed_files.txt

5. Combining with Other Git Commands:

You can combine git diff-tree with other Git commands to perform more complex tasks. For instance, to show the differences in the content of the changed files, you can use:

   git diff $(git diff-tree --no-commit-id --name-only -r $CI_COMMIT_SHA)