Switch to the default branch of a specified remote git repository

git-checkout-default

#!/usr/bin/env bash

set -e

USAGE="Usage:
    git-checkout-default <remote>"

# show help if requested
if [ "x$1" == "x-h" ] || [ "x$1" == "x-?" ] || [ "x$1" == "x--help" ]; then
    echo "Switch to the default branch of a specified remote git repository."
    echo "$USAGE"
    exit 0
fi

# assert remote supplied
if [ "x$1" == "x"  ]; then
    echo "No remote given, 'git-checkout-default -h' for help"
    echo "$USAGE"
    exit 1
fi

# find default branch for remote
git fetch "$1"
BRANCH=$(git remote show "$1" | sed -n '/HEAD branch/s/.*: //p')
if [ "x$BRANCH" == "x" ]; then
    echo "No branch found for $1"
    echo "$USAGE"
    exit 1
fi

# switch branch to default
if $(git show-ref --verify --quiet refs/heads/"$BRANCH"); then
    git switch "$BRANCH"
    exit 0
fi

git switch -c "$BRANCH" "$1"/"$BRANCH"