Simple bash script to create and switch master to main branch

redefault.sh

#!/bin/bash

set -euo pipefail

function git_branch {
    git branch 2>&1 | grep '^\*' | sed 's/\* //g'
}

function git_repo {
    grep 'url = git@github.com:' .git/config \
        | sed 's/^.*url = git@github.com://' \
        | sed 's/\.git$//'
}

function git_url {
    echo "https://github.com/$(git_repo)/settings/branches"
}

if ! git status 2>&1 | grep -q "nothing to commit"; then
    echo "Modifications detected. Aborting"
    exit 1
fi

if [[ $(git_branch) != "master" ]]; then
    echo "Will only execute from master branch"
    exit 1
fi

if git branch 2>&1 | grep -q 'main'; then
    echo "Found existing main branch: switching"
    git checkout main
else
    echo "Creating and switching to main branch"
    git checkout -b main
fi

if [[ $(git_branch) != "main" ]]; then
    echo "Why aren't we on the main branch?"
    return 1
fi

git rebase master

git push --set-upstream origin main

echo "Main branch created. Please update default branch now."

open "$(git_url)"