How to ignore files locally in git

Today I wanted to ignore some files locally while not dirtying the .gitignore file to avoid it appearing as a stageable change while running git status.

Possible solutions are explained in this Stackoverflow thread but are shown here verbatim:

Do not forget, according to gitignore, that there is an order of > precedence in the different “ignore pattern sources” that Git consider:

Patterns read from the command line for those commands that support them.

Patterns read from a .gitignore file in the same directory as the path, > or in any parent directory, with patterns in the higher level files (up to > the root) being overridden by those in lower level files down to the > directory containing the file.

Patterns read from $GIT_DIR/info/exclude.

Patterns read from the file specified by the configuration variable > core.excludesfile.

The last two can be a solution for your problem but:

they are not replicated for a distant repository

they can have their patterns overridden by the other sources

(See also this SO question)

The other two solutions involve updating the index (git update-index> ):

git update-index --assume-unchanged: see “Git: untrack a file in > local repo only and keep it in the remote repo”.
It is mentioned by Elijah Lynn in the comments.

You can even ignore a folder content: “git update-index > --assume-unchanged on directory”.

Use --no-assume-unchange to reverse the effect: See “Is it possible > to git add a file currently protected by assume-unchanged?”.

However, when you checkout another branch or when you git pull, that > “ignore” status might be reset. Hence the other option:

git update-index --skip-worktree; see:

“ignore my changes in files but don’t delete them from remote rep> “ and

“Preserve git –assume-unchanged files between branch checkouts”.

The difference between the two is explained in “Git - Difference Between > ‘assume-unchanged’ and ‘skip-worktree’”.

I ended up using the $GIT_DIR/info/exclude option.