Improved git docs

docs/Miscellaneous/Git.md

@@ -2,6 +2,49 @@
 
 <!-- toc -->
 
+## Move files from one repository to another, preserving git history
+
+_Based on Ayushya Jaiswal's excellent article on [Move files from one repository to another, preserving git
+history](https://medium.com/@XanderGrzy/how-to-move-files-from-one-git-repo-to-another-preserving-history-2e81e3e3c8b7)._
+
+In the example below, we want to extract a folder (`code/src/utils`) from a mono-repo (`repo1`) into its own repo (`repo2`), 
+preserving the git history.
+
+```shell
+git clone [email protected]:example/test.git repo1
+git clone [email protected]:example/test.git repo2
+cd repo2
+git remote rm origin
+git filter-branch --subdirectory-filter code/src/utils -- --all
+git reset --hard
+git gc --aggressive 
+git prune
+git clean -xfd
+```
+
+Now only the filtered folder is left, and it's at the root of repo2. If it's going into another repo with existing
+files, we can move the things to a sub-folder and commit them before proceeding, but in this case we want them in the
+root.
+
+Next, we push them to the new remote repo (which was created ahead of time and left empty):
+
+```shell
+git remote add origin [email protected]:example/test-extrusion.git
+git branch -M main
+git push -u origin main
+```
+
+Finally, we should clean up the old repo:
+
+```shell
+cd ../repo1
+rm -rf code/src/utils
+git add -A
+git commit
+```
+
+Obviously, there might be more refactoring needed, but this is the basic idea.
+
 ## Summarize changes
 
 ```shell
@@ -33,10 +76,6 @@ UI: [github.com/mhvelplund/git-bash](https://github.com/mhvelplund/git-bash).
 
 Credentials: [Storing Git Credentials with Git Credential Helper](https://techexpertise.medium.com/storing-git-credentials-with-git-credential-helper-33d22a6b5ce7)
 
-## Move files from one repository to another, preserving git history
-
-Excellent article [here](https://medium.com/@ayushya/move-directory-from-one-repository-to-another-preserving-git-history-d210fa049d4b).
-
 ## Move a feature branch from one product to another
 
 If, by accident, one has created a feature ``foo`` from the wrong product

docs/index.md

@@ -6,6 +6,7 @@ slay the same dragon twice.
 
 ## Notes
 
+- (2024-10-21) [Git](./Miscellaneous/Git.md)
 - (2024-10-15) [CLI tools](./DevOps/CLI.md)
 - (2024-08-07) [Shell scripting](./DevOps/BashScripting.md)
 - (2024-08-07) [Node.js & TypeScript](./Programming/Node.md)
@@ -16,7 +17,6 @@ slay the same dragon twice.
 - (2024-01-19) [Docker](./DevOps/Docker.md)
 - (2024-01-07) [Jupyter & Rust](./Programming/JupyterRust.md)
 - (2024-01-05) [Misc. Notes](./Miscellaneous/MiscNotes.md)
-- (2023-09-15) [Git](./Miscellaneous/Git.md)
 - (2023-09-14) [VS Code](./Miscellaneous/VS%20Code.md)
 - (2023-09-02) [Obsidian](./Miscellaneous/ObsidianNotes.md)
 - (2023-04-06) [Rust](./Programming/Rust.md)