untracked files still appear in git status

Question

I have untracked some folders and files by using .git/info/exclude :

doc
*.txt
doc/*.txt
doc/somefile.txt

But git status says it is still tracked :

$ git st
# On branch dev
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   doc/somefile.txt

Other weird thing is that ls-files shows it is untracked :

$ git ls-files --ignored --exclude-from=.git/info/exclude
doc/somefile.txt
$ touch /tmp/xxx
$ git ls-files --ignored --exclude-from=/tmp/xxx
$

I am on git version 1.8.1.5

So I conclude I may misunderstand something or do something wrong. Any idea please ?

Answer 1

Since you are locally ignoring files that are in the repository, you need to tell git that you are ignoring them

git update-index --assume-unchanged <files to forget>

Answer 2

You need to git rm --cached <file>. This doesn't remove the file from your working directory, but it removes it from the git cache so it'll now be included by the .gitignore.