Script to manage go versions easily

update_go.sh

#!/bin/bash
set -e

VERSION=$(curl -sS "https://go.dev/dl/?mode=json" | jq -r '.[0].version' | sed 's/go//')

INSTALL_DIR="/usr/local/go"
if [[ ! -d ${INSTALL_DIR} ]]; then
    echo "Install directory '${INSTALL_DIR}' does not exist, sudo required to create it..."
    sudo mkdir -p ${INSTALL_DIR}
fi
OWNED_BY=$(ls -ld ${INSTALL_DIR} | awk 'NR==1 {print $3}')
if [[ ${OWNED_BY} != $(whoami) ]]; then
    echo "Install directory not writable by current user, sudo required to change that..."
    sudo chown $(id -un):$(id -gn) ${INSTALL_DIR}
fi

VERSION_DIR="${INSTALL_DIR}/${VERSION}"
if [[ -d ${VERSION_DIR} ]]; then
    >&2 echo "${VERSION_DIR} already exists, don't know what to do with it."
    exit 1
fi

UNAME=$(uname | tr '[:upper:]' '[:lower:]')
ARCH="amd64"
if [[ $(uname -m) == "aarch64" ]]; then
    ARCH="arm64"
fi

DL_URL="https://dl.google.com/go/go${VERSION}.${UNAME}-${ARCH}.tar.gz"

if [[ -d /tmp/go ]]; then
    >&2 echo "/tmp/go already exists, don't know what to do with it."
    exit 1
fi

cd /tmp
curl -Ss ${DL_URL} | tar -xzf -
mv go ${VERSION_DIR}

rm -f ${INSTALL_DIR}/current
ln -s ${VERSION_DIR} ${INSTALL_DIR}/current

if [[ :$PATH: == *:"${INSTALL_DIR}/current/bin":* ]]; then
    echo "go updated to: $(go version)"
else
    echo "go ${VERSION} installed but is missing from your \$PATH"
    echo "Add the following line to your \$PATH variable:"
    echo "    ${INSTALL_DIR}/current/bin"
fi