Tracked

Tracked files are files that were in the last snapshot (ie head). They can have the status:

• unmodified,
• modified,
• or staged (ie in the index for the next commit)

Untracked

Untracked files are new files.

More specifically, they are any files in the working directory that:

• were not in the last snapshot
• and are not in the staging area (next commit).

Modification

• From untracked to deleted: git clean -f Git - Clean
• From staged to unmodified : git reset HEAD file Git - Reset (Unstaging) - Delete a change for the next commit
• From modified to unmodified : git checkout -- file What is a Git Checkout?
• From modified to staged: git add <file>... Git - Add command (Staging) - Add a change to the next commit

Get

git status

On branch master
Your branch is up-to-date with 'origin/master'.

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   syntax.php

no changes added to commit (use "git add" and/or "git commit -a")