Bash script that automatically updates to latest version of Terraform and TFlint

get-terraform.sh

#!/bin/bash
###########################################################################
# Update or install latest terraform/tflint binary versions, if existing version differ or is absent
# https://gist.github.com/needleshaped/0022791d1d4d4dc56ecfcce69083a248
##########################################################################

# Arguments and parameters
INSTALL_DIR="${1:-$HOME/bin}"
SUDO= # empty or "sudo"

# Checks
REGEX="^PATH=.*\K$INSTALL_DIR(?=.*)"
if [[ $(env | grep -oP "${REGEX}") != "$INSTALL_DIR" ]]; then
  echo "Looks like your install directory $INSTALL_DIR is not in your PATH. Make sure you export it"
fi

main_() {
  echo "Checking versions and installing, if necessary"

  INSTALLED_VERSION=$("$INSTALL_DIR"/terraform --version | grep -Poie '\d+.\d+.\d+')
  LATEST_VERSION=$(curl -s https://api.github.com/repos/hashicorp/terraform/releases/latest | grep -oP '"tag_name": "[v]\K(.*)(?=")')
  ZIP="terraform_${LATEST_VERSION}_linux_amd64.zip"
  URL="https://releases.hashicorp.com/terraform/${LATEST_VERSION}/${ZIP}"
  BINARY=terraform
  download_and_install

  INSTALLED_VERSION=$("$INSTALL_DIR"/tflint --version | awk '{if (NR == 1 ) print $3}')
  LATEST_VERSION=$(curl -s https://api.github.com/repos/terraform-linters/tflint/tags | grep -m1 -oP '"name": "[v]\K(.*)(?=")')
  ZIP="tflint_linux_amd64.zip"
  URL="https://github.com/terraform-linters/tflint/releases/download/${LATEST_VERSION}/${ZIP}"
  BINARY=tflint
  download_and_install
}

download_and_install() {
  if [[ "$LATEST_VERSION" != "$INSTALLED_VERSION" ]]; then
    echo "# Version mismatch, installing $BINARY $INSTALLED_VERSION > $LATEST_VERSION ..."
    cd /tmp
    wget -nv "$URL"
    $SUDO unzip -o "$ZIP" -d "$INSTALL_DIR" # or separately, install/rm, mv/chmod, etc
    rm -v "$ZIP"
    ls -la "${INSTALL_DIR}/$BINARY"*
    echo "# Done." 
  else
    echo "# Nothing done. Latest $BINARY, $INSTALLED_VERSION already installed."
  fi
}

main_