Installs Go locally in the current directory

go-install-locally.sh

#!/usr/bin/env bash
# Installs Go locally, in the current directory
# Usage:
#   ./go-install-locally.sh [GO_VERSION]
# Example:
#   ./install-go.sh 1.16
# The script will install Go 1.16 locally in the current directory.
# The script will only install Go if it is not already installed.
# The script will do nothing if Go is already installed.
main() {

  set -o errexit
  set -o pipefail
  set -o nounset

  local -r __dirname="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
  local -r __filename="${__dirname}/$(basename "${BASH_SOURCE[0]}")"

  GO_VERSION=${1:-1.16}

  echo "Checking if Go $GO_VERSION is already installed locally @ $__dirname/go"
  if [[ -f $__dirname/go/.installed-$GO_VERSION ]]; then
    echo "Go $GO_VERSION is already installed locally @ $__dirname/go"
    exit 0
  fi
  echo "Removing any existing Go installation @ $__dirname/go"
  rm -Rf go
  echo "Installing Go $GO_VERSION locally @ $__dirname/go"
  wget -cq https://go.dev/dl/go$GO_VERSION.linux-amd64.tar.gz -O - | tar xz

  touch $__dirname/go/.installed-$GO_VERSION
  echo "Go $GO_VERSION is now installed"

  exit 0
}
main "$@"