Download latest Go release and install to /opt

getgo.sh

#!/bin/sh

not_available() { echo -- "$1 is not available"; exit 1; }
ensure_command_available() { which -- "$1" >/dev/null && return; not_available "$1"; }
ensure_gnu_tar() { tar --version | grep -F 'GNU tar' >/dev/null || not_available 'GNU tar' }

ensure_command_available curl
ensure_command_available jq
ensure_gnu_tar

FILENAME=$(curl -fsSL 'https://golang.google.cn/dl/?mode=json' | jq -r 'map(select(.stable)) | .[0].files | map(select(.os == "linux" and .arch == "amd64")) | .[0].filename')
rm -rf /opt/go
echo "Downloading ${FILENAME}"
curl -fSL "https://dl.google.com/go/${FILENAME}" | tar --extract --gzip --directory=/opt