I wish to stop tracking files but still keep them in my working tree.
I've gathered that git rm --cached FILE will let me do that. However, if someone else pulls this change, will their local copies be deleted?
Yes, their copies will be automatically deleted. Imagine if this deletion wouldn't happen--then working copies of all users would be polluted with piles of deleted files, which aren't needed anymore.
However, if the remote users made local changes to these files, they won't be deleted, since pull will result in a merge conflict.
As Jefromi suggests in his comment, while the files are removed at the other users' sides, they can easily be restored--they're under a version-control, aren't they? ;-) Files could be gotten by git checkout <revision> -- <files...>. As revision you may specify the id of the previous commit, for pull it's saved in ORIG_HEAD (see this question for details):
git checkout ORIG_HEAD -- removed_file
In such a case I would rather ignore them locally only :
If they are already tracked :
git update-index --skip-worktree FILE
If they untracked : add them to your local exclude file
echo "FILE" >> .git/info/exclude
You can also have global .gitignore if its something you will do for all your repos (e.g. *~)
来源：https://stackoverflow.com/questions/3318637/will-git-rm-cached-delete-another-users-working-tree-files-when-they-pull