Switch between go version using https://github.com/golang/dl

switchgo.sh

function switchgo() {
  version=$1
  if [ -z $version ]; then
    echo "Usage: switchgo [version]"
    return
  fi

  if ! command -v "go$version" > /dev/null 2>&1; then
    echo "version does not exist, download with: "
    echo "  go get golang.org/dl/${version}"
    echo "  go${version} download"
    return
  fi

  go_bin_path=$(command -v "go$version")
  ln -sf "$go_bin_path" "$GOBIN/go"
  echo "Switched to ${go_bin_path}"
}