How do I "tell" git to ignore a file that has already been in multiple commits (git .ignore doesn't work for some reason)?

Question

git

Forgot to add some files to git .ignore initially.
Accordingly, they ended up in several commits, and I don’t need them there at all.
When you add the names of these git .ignore files, nothing happens. Git continues to handle them diligently.
What could be the reason for this behavior and how can it be overcome?

Answer 1

git rm --cached file.txt

Answer 2

To be honest, your question is not entirely clear.
But if you added some information to the repository, and now you want git to forget it forever, including removing a file from the commit history (for example, a file with a password, or personal information), then look here:
https://help.github .com/articles/remove-sensitive-data/