#!/bin/bash

MONTH=$(( $(date +%m) - 1 ))
if [ "x$1" == "x" ]
then
    YEAR=$(( $(date +%Y) - 1))
else
	YEAR=$1
fi

if [ $MONTH -eq 0 ];
then
	MONTH=12
  YEAR=$(( $YEAR - 1))
fi

tar -cvJf $YEAR.tar.xz $YEAR-*.tar.xz && rm -v $YEAR-*.tar.xz