A bash script which renames branches recursively.

rename_branches.sh

#!/bin/env bash
# This script is public domain.
# If your government doesn't allow that, it doesn't matter. What're they gonna do? Sue me?
# Just a useful script for changing the name of your repo.

# Variables
ROOT_FOLDER=~/
OLD=${1:-main}
NEW=${2:-master}

case $1 in
	--help)
		# Print a help message and exit
		echo "Usage: ./rename_branches.sh [old_branch] [new_branch]"
		echo "This script will change the name of all git repos in subfolders of ${ROOT_FOLDER} from old_branch to new_branch."
		echo "If no arguments are provided, it will use default values defined in the script."
		echo "Use at your own risk!"
		exit 0
		;;
esac

echo "This script will changes the name of all git repos"
echo "in subfolders of ${ROOT_FOLDER} from '${OLD}' to '${NEW}'!"
echo "Use at your own risk!"

set -e

for FOLDER in $(find ${ROOT_FOLDER} -name ".git" | sed "s/.git$//")
do
	echo "${FOLDER}"
	# Check if the folder is a valid git repo
	if [ -d "${FOLDER}/.git" ]; then
		read -rp "Rename ${OLD} to ${NEW}? " yn
		case $yn in
			[Yy]* ) 
				cd "${FOLDER}"
				# Check if the old branch exists
				if git show-ref --verify --quiet "refs/heads/${OLD}"; then
					git branch -m "${OLD}" "${NEW}"
					# Check if the remote origin exists
					if git ls-remote --exit-code origin &>/dev/null; then
						git push -u origin "${NEW}"
						git push origin --delete "${OLD}"
					else
						echo "Remote origin does not exist."
					fi
				else
					echo "Branch ${OLD} does not exist."
				fi
				;;
			[Nn]* ) echo Skipped repo; continue;;
			* ) echo "Please answer yes or no.";;
		esac
	else
		echo "Not a valid git repo."
	fi
	echo ""
done

echo "Script finished."