Bash script to install the latest version of go or update Go to the latest version. Caches downloads so you won't do work twice.

install-go.sh

#!/bin/bash
# This script installs the latest version of Go on your system.
# _________ _        _______ _________ _______  _        _          _______  _______   
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# ___) (___| )  \  |/\____) |   | |   | )   ( || (____/\| (____/\  | (___) || (___) |  
# \_______/|/    )_)\_______)   )_(   |/     \|(_______/(_______/  (_______)(_______)  
#
# Generated with https://patorjk.com/software/taag/#p=display&f=Graffiti&t=                                                                         

# Check if Go is already installed
if command -v go &>/dev/null; then
  # Check the current version of Go
  CURRENT_VERSION=$(go version | awk '{print $3}')
  echo "Current version: ${CURRENT_VERSION}"
else
  echo "Go is not installed."
  CURRENT_VERSION=""
fi

# Get the latest version of Go
GO_VERSION=$(curl -SsL https://golang.org/VERSION?m=text)

# If installed version is the latest version, no work to do
if [[ "${GO_VERSION}" == "${CURRENT_VERSION}" ]]; then
  echo "Latest version ${CURRENT_VERSION} is already installed."
  exit 0
fi

if [ -f "${HOME}/.cache/go_${GO_VERSION}.tar.gz" ]; then
  echo "Found Go ${GO_VERSION} archive in cache. Using it instead of downloading again."
  GO_ARCHIVE="${HOME}/.cache/go_${GO_VERSION}.tar.gz"
else
  echo "Go ${GO_VERSION} archive not found in cache. Downloading latest version of Go."
  GO_ARCHIVE="/tmp/go_${GO_VERSION}.tar.gz"
  wget https://dl.google.com/go/${GO_VERSION}.linux-amd64.tar.gz -O "${GO_ARCHIVE}"
  # Save the archive to the cache
  cp "${GO_ARCHIVE}" "${HOME}/.cache/go_${GO_VERSION}.tar.gz"
fi

# Extract the archive to /usr/local/go
sudo tar -C /usr/local -xzf "${GO_ARCHIVE}"

if [[ ":$PATH:" == *":/usr/local/go/bin:"* ]]; then
  echo "Go is already in your PATH."
else
  echo "Go is not in your PATH."
  echo "Would you like to add it to your PATH? (y/n)"
  read answer
  if [[ $answer == "y" ]]; then
    # Set up the environment variables for Go
    rc_file="${HOME}/.$(basename "${SHELL}")rc"
    echo 'export GOPATH=$HOME/go' >> "${rc_file}"
    echo 'export PATH=$PATH:/usr/local/go/bin' >> "${rc_file}"
    echo 'export PATH=$PATH:$GOPATH/bin' >> "${rc_file}"
    source "${rc_file}"
    echo "Go has been added to your PATH."
  else
    echo "Go has not been added to your PATH."
    echo "To use Go, you will need to add it to your PATH manually."
  fi
fi

# Check the version of Go
if [ -n "${CURRENT_VERSION}" ]; then
  INSTALLED_VERSION="${CURRENT_VERSION}"
else
  INSTALLED_VERSION=$(go version | awk '{print $3}')
fi

echo "Installed version: ${INSTALLED_VERSION}"
echo "Latest version: ${GO_VERSION}"
echo "Go has been updated to the latest version."