tapebackup

#!/bin/sh -eu
#dump -h 0 -u -a -b 256 -f /dev/nst0 -j9 -Q /tmp/root.qfa -0 /dev/mapper/box-root_ubuntu
DUMPOPTS=""
TAPE="/dev/nst0"

usage() {
	echo "Usage: $(basename "${0}") [-t ${TAPE}] -[0-9] TARGET [...]"
}

while getopts ":h0123456789t:" opt; do
	case ${opt} in
		[0-9] ) LEVEL="$opt" ;;
		t ) TAPE="$OPTARG" ;;
		h ) usage ; exit 0; ;;
		? ) echo "Invalid Option: -$OPTARG" 1>&2; usage 1>&2;  exit 1; ;;
	esac
done
shift $((OPTIND -1))

if [ -z "${TAPE:-}" ]
then
	echo "Tape is required" 1>&2; usage 1>&2;
	exit 1
fi

if [ -z "${*:-}" ]
then
	echo "Target is required\n" 1>&2
	dump -w 1>&2	
	echo 1>&2
	usage 1>&2
	exit 1
fi

if [ -z "${LEVEL:-}" ]
then
	echo "Level is required\n" 1>&2
	dump -w 1>&2	
	echo 1>&2
	usage 1>&2
	exit 1
fi

tell() {
	mt -f "${TAPE}" tell | grep -o '[0-9]*'
}

for target
do
	pos="$( (grep EOT tape || echo "0 EOT") | cut -d " " -f1 )"
	mt -f "${TAPE}" seek "${pos}"

	target_name="$(basename "${target}")"
	slug="${target_name##*-}"
	pos="$(tell)"
	qfa="${slug}-${pos}.qfa"

	dump -h 0 -u -a -b 256 ${DUMPOPTS:-} -f "${TAPE}" -Q "${qfa}" "-${LEVEL}" "${target}"
	
	tmptape="$(mktemp tape.XXXXXXXXXX)"
	(
		grep -v -e "^${pos}\s" tape
		echo "${pos} dump ${slug} ${LEVEL:-} ${DUMPOPTS:-}"
		echo "$(tell) EOT"
	) > "${tmptape}"
	shtool rotate tape
	mv "${tmptape}" tape
done