When we are working inside our Git repository and we run git add . in order to prepare things for a commit, sometimes we’ll see unwanted files being staged and we’ll have to manually remove them by running git rm --cached <filename>. But there’s a better way! We can tell Git to automatically ignore certain files or directories by using a .gitignore file.
We can create local or global .gitignore files.
Local .gitignore file
We can create a .gitignore file in our project’s root folder to ignore items that are specific to this project. For example, when I’m working on my blog using Jekyll, a folder named _site containing all the generated HTML will be created. To prevent it from being committed, we can create a local .gitignore file like this:
$ cd myblog
$ echo "_site/" > .gitignore
That way the _site folder will never be committed by mistake.
Global .gitignore file
When we navigate through folders using Mac’s Finder it will generate hidden .DS_Store files all over the place. Instead of adding .DS_Store to all the different .gitignore files in our various projects, we can create a global .gitignore like this:
$ cd ~
$ echo ".DS_Store" > .gitignore
Git doesn’t automatically pick up this global .gitignore file. We need to add it to our .gitconfig. Although we can do it manually by editing the file with our favourite text editor, it may be easier to just run the following command in our terminal:
$ git config --global core.excludesfile "~/.gitignore"
We’ll never see a .DS_Store file again!