Install a DMG file via CLI.

install.sh

#!/bin/bash

# see: https://apple.stackexchange.com/a/311511/291269
function install_dmg {

    set -x

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    # Initialize a variable for the URL to the '.dmg'

    local -r URL="$1"

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    # Create temporary directory to store '.dmg'

    TMP_DIRECTORY="$(mktemp -d)"

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    #  Obtain the '.dmg' via cURL

    curl -s "$URL" > "$TMP_DIRECTORY/pkg.dmg"

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    # Mount the '.dmg' then grab its PATH

    DISK="$(sudo hdiutil attach "$TMP_DIRECTORY"/pkg.dmg | grep Volumes)"
    VOLUME="$(echo "$DISK" | cut -f 3)"

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    # Install the program within the '.dmg'

    if [ -e "$VOLUME"/*.app ]; then
      sudo cp -rf "$VOLUME"/*.app /Applications
    elif [ -e "$VOLUME"/*.pkg ]; then
      package="$(ls -1 | grep *.pkg | head -1)"

      sudo installer -pkg "$VOLUME"/"$package".pkg -target /
    fi

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    # Eject the '.dmg'

    sudo hdiutil detach "$(echo "$DISK" | cut -f 1)"

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    # Remove the temporary directory

    rm -rf "$TMP_DIRECTORY"

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    set +x

}