Tracking changes

The files in your working directory can be in one of two states: tracked or untracked.

• Tracked files are files that were include in the last snapshot. They can be unmodified, modified, or staged. By definition, these files are tracked by the Git index (staging area).
• Untracked files are any files in your working directory that were not in your last snapshot and are not in your staging area. When you first clone a repository, all of your files will be tracked and unmodified because they were in the last snapshot. As you modify files, Git sees them as modified because you have changed them since your last commit. You stage these modified files and then commit them to save the snapshot permanently in your Git directory.

Git commands to track changes

• git status - Shows the status of changes as untracked, modified, or staged
• git add - Adds changes to the staging area
• git commit - Saves the snapshot permanently in your Git directory

The following screenshots show the progression of changes to the working directory and how they are tracked by Git.

In the first screenshot, you can see that the local working directory contains one file, README.md. The git status command shows the working tree is clean. Next, the README.md files is edited and two license files are copied from another location. The git status command shows one modified file and two untracked files. Notice how the prompt changes with each command.

The git add command is used to add a license file to the staging area. The git status command shows that LICENSE-CODE.md is now staged.

The git add -A command adds all files to the staging area. The git status command shows that all three files are now staged.

The git commit command is used to save the changes to the local repository. Finally, the git push command is used to push the changes to GitHub.

Now we can see the changes in GitHub. The README.md file is shown with the changes and the two license files are shown as new files.