Let's say we have a file that was inadvertently added to our repository:
stackoverflow$ echo this file is important > junkfile
stackoverflow$ git add junkfile
stackoverflow$ git ci -m 'added a file'
At some point, we realize that the file is unimportant so we add it to our .gitignore file:
stackoverflow$ echo junkfile >> .gitignore
stackoverflow$ git ci -m 'ignore junkfile' .gitignore
Later on, we make some changes to that file:
stackoverflow$ sed -i 's/ is / is not/' junkfile
And of course, even though the file is listed in .gitignore, we have already told git that we want to track it, so git status shows:
stackoverflow$ git status
# On branch master
# 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: junkfile
#
no changes added to commit (use "git add" and/or "git commit -a")
We need to remove this file from the repository (without removing the file from our work tree). We can do this with the --cached flag to git rm:
stackoverflow$ git rm --cached junkfile
rm 'junkfile'
This stages the delete operation...
stackoverflow$ git status
# On branch master
# Changes to be committed:
# (use "git reset HEAD <file>..." to unstage)
#
# deleted: junkfile
#
...so we need to commit it:
stackoverflow$ git commit -m 'removed junkfile from repository'
[master 19f082a] removed junkfile from repository
1 file changed, 1 deletion(-)
delete mode 100644 junkfile
Now if we run git status git will ignore this file:
stackoverflow$ git status
# On branch master
nothing to commit, working directory clean
Even though it's still here in our working tree:
stackoverflow$ cat junkfile
this file is not important
