I have a git repository hosted on Github. After committing many files, I am realizing that I need to create .gitignore and exclude .exe, .obj files.
However, will it automatically remove these committed files from the repository? Is there any way to force that?
No you cannot force a file that is already committed in the repo to be removed just because it is added to the .gitignore
You have to git rm --cached to remove the files that you don't want in the repo. ( --cached since you probably want to keep the local copy but remove from the repo. ) So if you want to remove all the exe's from your repo do
git rm --cached /\*.exe
(Note that the asterisk * is quoted from the shell - this lets git, and not the shell, expand the pathnames of files and subdirectories)
However, will it automatically remove these committed files from the repository?
No. Even with an existing .gitignore you are able to stage "ignored" files with the -f (force) flag. If they files are already commited, they don't get removed automatically.
git rm --cached path/to/ignored.exe
If you have not pushed the changes already:
git rm -r --cached .
git add .
git commit -m 'clear git cache'
git push
I had to remove .idea and target folders and after reading all comments this worked for me:
git rm -r .idea
git rm -r target
git commit -m 'removed .idea folder'
and then push to master
However, will it automatically remove these committed files from the repository?
No.
The 'best' recipe to do this is using git filter-branch as written about here:
The man page for git-filter-branch contains comprehensive examples.
Note You'll be re-writing history. If you had published any revisions containing the accidentally added files, this could create trouble for users of those public branches. Inform them, or perhaps think about how badly you need to remove the files.
Note In the presence of tags, always use the --tag-name-filter cat option to git filter-branch. It never hurts and will save you the head-ache when you realize later taht you needed it
Even after you delete the file(s) and then commit, you will still have those files in history. To delete those, consider using BFG Repo-Cleaner. It is an alternative to git-filter-branch.
来源：https://stackoverflow.com/questions/6535362/gitignore-after-commit