Add Configure Global gitignore File as a git til

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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@@ -221,6 +221,7 @@ _996 TILs and counting..._
 - [Clean Out All Local Branches](git/clean-out-all-local-branches.md)
 - [Clean Up Old Remote Tracking References](git/clean-up-old-remote-tracking-references.md)
 - [Clone A Repo Locally From .git](git/clone-a-repo-locally-from-git.md)
+- [Configure Global gitignore File](git/configure-global-gitignore-file.md)
 - [Configuring The Pager](git/configuring-the-pager.md)
 - [Delete All Untracked Files](git/delete-all-untracked-files.md)
 - [Determine The Hash Id For A Blob](git/determine-the-hash-id-for-a-blob.md)

git/configure-global-gitignore-file.md

@@ -0,0 +1,33 @@
+# Configure Global gitignore File
+
+There are some files that you know you'll never want tracked by git. You don't
+even want them showing up as an option. For these files, it can be nice to
+specify them in a global `.gitignore` file. Then you don't need to specify them
+for each project.
+
+This can be configured in `~/.gitconfig` under the `core` settings as
+`excludesFile`.
+
+```
+[core]
+	excludesFile = ~/.gitignore
+```
+
+Then, create `~/.gitignore` (that's as good a place as any to put it).
+
+```
+# global .gitignore
+.DS_Store
+wip_notes.md
+```
+
+You'll now notice that for any git project, the files you listed won't be
+showing up in the untracked list.
+
+You can also add this to your `~/.gitconfig` with this one-line command.
+
+```bash
+$ git config --global core.excludesfile ~/.gitignore
+```
+
+See `man git-config` and search `core.excludesFile` for more details.