How to ignore existing file in Git?

Question

I need to work on file.txt locally and in Git, with different content. I want Git not to tell me that there have been changes to that file.

Is this possible

Answer 1

Actually, you want --skip-worktree, not --assume-unchanged. Here's a good explanation why.

So git update-index --skip-worktree file.txt

TLDR; --assume-unchanged is for performance, for files that won't change (like SDKs); --skip-worktree is for files that exist on remote but that you want to make local (untracked) changes to.