To run it automatically when computer turns off past this file to /etc/init.d/ folder and create a symbol link to it in /etc/rc0.d and /etc/rc6.d. At least that what I have red in this [article](https://askubuntu.com/questions/83473/how-to-execute-script-on-shutdown)

save_repo_in_private_remote_git.sh

#!/usr/bin/env bash

REPO_PATH='/media/user/Documents/Repo_folder'
BRANCH_NAME='laptop_dell_vostro_3590'

if [ -d '/media/user/Documents/Repo_folder' ] 
then
  DATE=$(date)

  cd '/media/user/Documents/Repo_folder'
  
  EXISTS=`git show-ref refs/heads/$BRANCH_NAME`

	if [ -n "$EXISTS" ]
	then
	    git checkout $BRANCH_NAME
	else
		git checkout master
		git checkout -b $BRANCH_NAME
	fi

	git pull

	git add .

  git commit -m "Changes added on $DATE"

  git push --set-upstream origin $BRANCH_NAME
else
	FAILURE_MESSAGE="Directory $REPO_PATH DOES NOT exists."
	echo $FAILURE_MESSAGE 
	exit 9999 # die with error code 9999
fi