#!/bin/sh

if which pacman >/dev/null 2>&1; then
  # arch linux
  running=$(
    uname -r | \
      sed '
        s|-ARCH$||
      '
  )
  installed=$(
    pacman -Q linux | \
      cut -d' ' -f2
  )
elif which apt >/dev/null 2>&1; then
  # debian
  running=$(
    uname -r
  )
  installed=$(
    dpkg-query -W 'linux-image-*-?86' | \
      cut -f1 | \
      sed '
        s|^linux-image-||
      ' | \
      sort -V | \
      tail -n1
  )
else
  >&2 printf 'Cannot determin installed kernel.\n'
  exit 2
fi

if [ "${running}" = "${installed}" ]; then
  >&2 printf 'The installed kernel (%s) is currently running.\n' \
    "${installed}"
  exit 0
else
  >&2 printf 'The installed (%s) and running kernel (%s) differ.\n' \
    "${installed}" \
    "${running}"
  exit 1
fi