gitignore - Exclude specific files from 'git pull'

Question

I have a production git repo that I only pull changes from the main repo into; I never change this repo or do commits/pushes from here. I recently accidentally pushed some untracked (at least I thought they were) image files to the main repo from my local dev repo. Now when I try to pull the latest from the main repo, git reports an error regarding overwriting the exiting image file with the file from the main repo. I don't even want this file from the repo (it's located in a ,gitignored directory on the production repo)

How can I a) get rid of these unwanted image files in my main repo, or b) exclude these files from my git pull?

Answer 1

This allowed me to tell git to ignore a specific file, even though it was already part of a project. All changes I make to it will be ignored:

git update-index --assume-unchanged Localization/el-GR.js

Source: http://codethug.com/2013/09/20/4-ways-to-ignore-files-with-git/