install-packages

#!/bin/bash -eu

_mode="$(
    _self="${0##*/}"
    case "$_self" in
    'install-packages' | 'upgrade-packages')
        : "${_self%%-*}"
        ;;
    *)
        :
        ;;
    esac
    printf '%s\n' "$_" # Return value
)"

test "$_mode" == ':' && printf '%s\n' 'Invalid mode' && exit 1
if test "$_mode" == 'install' && [ $# = 0 ]; then
    echo >&2 "No packages specified"
    exit 1
fi

# Block users from running this unless they're root.
if [[ $EUID != 0 ]]; then
    echo >&2 "Run this script again as root to $_mode packages."
    exit 1
fi

# Set a runlevel to avoid invoke-rc.d warnings
# http://manpages.ubuntu.com/manpages/focal/man8/runlevel.8.html#environment
# shellcheck disable=SC2034
RUNLEVEL=1

DAZZLE_MARKS="/var/lib/apt/dazzle-marks/"
TIMESTAMP=$(date +%s)

if [ ! -d "${DAZZLE_MARKS}" ]; then
    mkdir -p "${DAZZLE_MARKS}"
fi

debconf-set-selections <<<'debconf debconf/frontend select Noninteractive'
apt-get update
apt-get "$_mode" -yq --no-install-recommends "$@"
debconf-set-selections <<<'debconf debconf/frontend select Readline'

cp /var/lib/dpkg/status "${DAZZLE_MARKS}/${TIMESTAMP}.status"

apt-get clean -y

rm -rf \
    /var/cache/debconf/* \
    /var/lib/apt/lists/* \
    /tmp/* \
    /var/tmp/*