title: How to ignore files which is already versioned by git?
body: <p>For example, when I run my java project in my local machine ,I want always comment some code which is used for user identification ,but of course, these local modification should never be commited and pushed to the remote. What can I do ? I know <strong>.gitignore</strong> file, but as I know , this can only be used for files <strong>which is not versioned by git</strong>.So any suggestions?</p>