1. Remove any files already added form the working directory. For example:
$ git rm -f *dwsync.xml

2. Set up (or create) your global git ignore file in your home directory:
$ printf "dwsync.xmlnThumbs.dbn" >> ~/.gitignore

3. using git config add this to you git prefs
(For repos that may be worked on by multiple users you should also create this file at the root of your working directory.)
$ git config --global core.excludesfile ~/.gitignore

References
hcodep://jqr.github.com/2009/02/03/global-git-ignore.html
hcodep://help.github.com/ignore-files/

Last updated on 5th September 2018