How to Put Everything in Git

It's good to get in the habit of putting everything into a git repo, and that means having a canonical remote for experiments. Creating remotes for each experiment becomes a clutter of keys and repos. So it's best to merge all of those experiments into a larger experiments repo and just push that repo to github.

Instead of thousands of repos, consolidate your configs and experiments into a single repo on your development machine like so:

In this case I needed a simple main.c to test ARM support for NEON (like SSE on intel) on Raspberry PI. The directory was primitive, but I still wanted to retain the experiment:

 - arm_neon/ 
      - main.c
      - .gitignore

To preserve this repo, I still use git init and manage commits within arm_neon locally, but "subtree" it into an experiments repo using git subtree add . Here are the steps.

1. Initialize and Commit the Experiment locally on Raspberry Pi

cd arm_neon
git init
git add -u
git commit -m "arm register test working"

2. Add the arm_neon Experiment Remote

On the development machine , add the arm_neon experiment as a remote within the experiments repo.

cd experiments
git remote add arm_neon ssh://[e-mail]/home/pi/test/arm_neon
git fetch arm_neon
# git warns you the two repos have nothing in common-- as expected
warning: no common commits

Add the subtree using arm_neon as the prefix (the directory)

PREFIX=arm_neon
REMOTE=arm_neon
git subtree add -P $PREFIX $REMOTE master

Test that it worked

git log -1
93dc44e - (tag: arm_neon_latest, tonymet/master) Add 'arm_neon/' from commit '083a748c92a4b04caa667c3573de4fb0c46c86fc' (33 minutes ago) <Anthony Metzidis>

3. Push the Experiments to Github

Now experiments contains arm_neon and hundreds of others. Push it up to github.

git push github HEAD

4. Continue Experimentation & Tracking Changes

Now that the two repos are linked, you can continue making changes to arm_neon and use git subtree merge to incorporate the latest commits.

# on raspberry pi, a new commit has been made
 git log
3d7315a - (HEAD -> master) improve docs (11 seconds ago) <Anthony Metzidis>
083a748 - arm neon call (26 minutes ago) <Anthony Metzidis> 

now merge those changes into the experiments repo

# get latest changes on development machine
git fetch arm_neon
# merge those into the subtree .
git subtree merge arm_neon/master -P arm_neon

Now the experiments repo contains all the latest changes from arm_neon, and can be pushed to github.

git log -1
93dc44e - (HEAD -> master) Add 'arm_neon/' from commit '083a748c92a4b04caa667c3573de4fb0c46c86fc' (5 seconds ago) <Anthony Metzidis>

Now you have one repo that contains hundreds of experiments , rather than creating hundreds of repos in your github account.