kinstall.sh

#!/bin/sh
set -efu
export DEBIAN_FRONTEND=noninteractive
FALLBACK=0
APT_MAIN=0
DONE=0
khpkg=""
kernel="$(uname -r || :)"
if [ -z "$kernel" ]; then
	echo "Unable to get kernel version, trying fallback"
	FALLBACK=1
fi
if [ "$FALLBACK" = 0 ] && [ ! -d "/lib/modules/${kernel}/kernel" ]; then
	echo "Detected kernel not found on this sytem, probably running in container?"
	echo "Trying fallback"
	FALLBACK=1
fi
if [ "$FALLBACK" = 0 ]; then
	khpkg="linux-headers-${kernel}"
	if ! LC_ALL=C apt policy "$khpkg" | grep -q 'Unable to locate package'
		then APT_MAIN=0
		else APT_MAIN=1
	fi
fi
if [ "$APT_MAIN" = 1 ]; then
	if apt install -y "$khpkg" ; then
		DONE=1
	fi
fi
if [ "$DONE" = 0 ]; then
	if apt install "blablabla" ; then
		DONE=1
	fi
fi
if [ "$DONE" = 0 ]; then
	echo "Error"
	exit 1
fi