A global .gitignore file allows you to specify patterns for files and directories that should be ignored by Git across all repositories on your system.

macOS and .DS_Store

macOS creates a .DS_Store file inside any directory you view with Finder. This has been something that has annoyed me about using my MacBook for casual editing. After reading man git-config, I came across a method to ignore this across all repositories instead of modifying each one with a .gitignore.

core.excludesFile -
Specifies the pathname to the file that contains patterns to describe paths that are not meant to be tracked, in addition to .gitignore (per-directory) and .git/info/exclude. Defaults to $XDG_CONFIG_HOME/git/ignore. If $XDG_CONFIG_HOME is either not set or empty, $HOME/.config/git/ignore is used instead. See gitignore(5).

Success! This is exactly what I needed. Without further delay, lets see this in action.

Here is a step-by-step guide to create a global .gitignore file:

  1. Create the .config directory and the accompanying ignore file. Since this is macOS, you will not have any of the XDG variables, so we substitute them for their fallback.

     $ mkdir --parents ~/.config/git/
 $ touch ~/.config/git/ignore

  2. Add the patterns for the files you want to ignore, in my case the dreaded .DS_Store files. You can also take this opportunity to include other things you wish to ignore globally, such as .swp files come to mind if you are a heavy Vim user.

    Contents of ~/.config/git/ignore:

     # Ignore macOS system files
 .DS_Store

  3. Verify things are working by checking for the presence of a .DS_Store in a git directory.

     tcloud@MacBookPro devcontainer-base-images % ls -1A
 .DS_Store
 .git
 .github
 .gitmodules
 .submodules
 .vscode
 COPYING
 Containerfile.ArchLinux
 Containerfile.Fedora
 Containerfile.UbuntuLTS
 Containerfile.template
 README.md
 devcontainer.json.template

 tcloud@MacBookPro devcontainer-base-images % git status
 On branch main
 Your branch is up to date with 'origin/main'.

 nothing to commit, working tree clean

    No .gitignore for this repository and no pending changes!

Wrapping Up

This wasn’t a particulary exciting post, but it was something that has bothered me for a while. I was just recently bothered enough by it to investigate and thought I should document it here for others. A special shout out to a colleague of mine for making me pursue this. Without their bug report on my devcontainer project, I may not have investigated this issue.