Pod install script that automatically runs `pod install --repo-update` when appropriate

pod_install.sh

# Install Pods and use `--repo-update` if needed (might need to add sudo for the gem command below)
set -e

if [ -f "./Podfile" ] && [ ! -d "./Pods" ]; then
    echo "Podfile found and Pods are not checked-in to git; installing Pods"
    if [ -f "./Podfile.lock" ]; then
        current_version=`pod --version | xargs echo -n`
        podfile_version=`cat Podfile.lock | grep -E 'COCOAPODS: \d(\.\d)*' | sed -E 's/COCOAPODS: (.*)/\1/' | xargs echo -n`
        if [ "$current_version" != podfile_version ]; then
            echo "Cocoapods version $current_version doesn't match the Podfile.lock version $podfile_version, installing Podfile.lock version"
            gem cleanup cocoapods || true
            gem uninstall cocoapods xcodeproj -ax --force || true
            gem install cocoapods -N --force --version "$podfile_version"
        else
            echo "Cocoapods version $current_version matches the Podfile.lock version"
        fi
    fi

    set +e
    pod install
    error_code=$?
    set -e
    if [ $error_code -eq 31 ]; then
        echo "Local specs is not up-to-date, re-running pod install and updating the local spec repo."
        pod install --repo-update
    else
        exit $error_code
    fi
else
    echo "Podfile not found or Pods folder is checked-in to git; not installing Pods"
fi