dar easy backup

dar-differential-backup.sh

#!/bin/bash

# cron setting example
# 5 3 * * *  ionice -c2 -n7 nice -n19 /usr/local/sbin/dar-differential-backup.sh >/dev/null 2>&1
#   or
# ALLNICE="ionice -c2 -n7 nice -n19"
# BACKUP_SCRIPT="/usr/local/sbin/dar-differential-backup.sh"
# 5 3 * * 0           $ALLNICE $BACKUP_SCRIPT -f >/dev/null 2>&1
# 5 3 * * 1,2,3,4,5,6 $ALLNICE $BACKUP_SCRIPT -d >/dev/null 2>&1


set -e
set -x

BACKUP_DIR=/backup
DAR=/usr/bin/dar
DAR_ARGS="-R / -w -z -Q"
WEEK_ROTATE=5

if [ -z "$TARGET_DIRS" ]; then
	TARGET_DIRS="-g home -g etc -g root -g usr/local"
fi

if [ -z "$DO_NOT_COMPRESSIONS" ]; then
	DO_NOT_COMPRESSIONS="-Z *.gz -Z *.png -Z *.jpg -Z *.jpeg -Z *.bz2"
fi

if [ -z "$EXCLUDES" ]; then
	EXCLUDES="-X *.swp -X *.tmp -X *.org -X *.pid -X lock -X *~"
fi


day_of_first_in_week(){

	date +%Y%m%d --date "$(date +%w) days ago"
}

today(){
	date +%Y%m%d
}

full_backup_archive_name(){

	local day=$1
	if [ -z "$day" ]; then
		day=$(day_of_first_in_week)
	fi
	ls $BACKUP_DIR/$day/*-full*.dar 2>/dev/null | sed -e 's/^\(.*-full\).*$/\1/'
}

rotate_backup_dir(){

	local work_dirs=($(ls -1 -d $BACKUP_DIR/* 2>/dev/null | sort -nr))
	while [ ${#work_dirs[@]} -gt $WEEK_ROTATE ]; do
		local last_index=$((${#work_dirs[@]} - 1))
		rm -fr ${work_dirs[$last_index]}
		unset work_dirs[$last_index]
	done
}

### start ###
work_dir=$BACKUP_DIR/$(day_of_first_in_week)
full_backup_base=$(full_backup_archive_name)

# getopt
while getopts fd OPT; do
  case $OPT in
    "f" ) type="full"; mkdir -p $work_dir;;
    "d" ) type="diff";;
    "a" ) type="auto";;
  esac
done
if [ -z "$type" ]; then
	type="auto"
fi


# make backup directory
if [ "$type" = "auto" ]; then
	if [ ! -d $work_dir ]; then
		mkdir -p $work_dir
		type="full"
	else
		if [ -z "$full_backup_base" ] ; then
			type="full"
		else
			type="diff"
		fi
	fi
fi

rotate_backup_dir


archive_base=$work_dir/$(today)-$type


dar_args="$DAR_ARGS $TARGET_DIRS $DO_NOT_COMPRESSIONS $EXCLUDES -c $archive_base"
if [ $type = "diff" ]; then
	dar_args="$dar_args -A $full_backup_base"
fi

eval $(echo $DAR $dar_args)