Simple rsync based incremental and snapshot backup script

BACKUP

This was created as a helper script for backing up my directory with VMs

It's not the prettiest one, but it's very simple and flexible. Works for me!

Be careful with the remove-old option, you may want to back up some of the older back ups to another place,
since it removers EVERY BACKUP OLDER than a week.

You definitely want the backup root to be a separate partition or, even better, separate disk.

It can be put into cron, if you do so I'd suggest a wrapper script like this:

mount -o remount,rw backup_part
* execute backup script *
mount - remount,ro backup_part

TODO: 
  - option for compressing old backups with tar.
  - ass option to override default backup root dir with shell, like this:
  $ BACKUP_ROOT=/foo/bar ./backup.sh make baz

Not tested on anything else than my VM server (debian 9.2). Your mileage may vary. CA residents add 5kb bash tax.

Notes: 
  - If you are on debian 9 you might have to install rsync, if you haven't yet.
  - On creating the first backup, rm might complain for no such file or directory. This is normal.
    If you repeat the backup again, it should not
  - Since my VM server is spun up whenever it needs and I might need to back up often, my timestamp version is very precise.
    You may want to change it to something day-precise, or hour-precise: `date +%F-%Hh` or simply `date +%F`

backup.sh

#!/bin/bash
echo "Backup script v0.1"

# The directory where the backups are stored
BACKUP_ROOT='/var/bkp/'
# Dir name for last backup link
LASTONE='lastbkp'
# Timestamp format
TIMESTAMP=`date +%F-%T`
# Directory to be backed up
SUBJECT=${2%/} # Remove trailing /


case $1 in
	"make")
		# Create backup directories if they don't exist
		if [ ! -d "${BACKUP_ROOT}" ]; then echo "${BACKUP_ROOT} did not exist; creating it"; mkdir ${BACKUP_ROOT}; fi	
		if [ ! -d "${BACKUP_ROOT}/$LASTONE-$SUBJECT" ]; then echo "${BACKUP_ROOT}/$LASTONE-$SUBJECT did not exist; creating it"; mkdir ${BACKUP_ROOT}/$LASTONE-$SUBJECT; fi
		# Synchronize files
		rsync -av --progress --link-dest $BACKUP_ROOT/$LASTONE-$SUBJECT "$SUBJECT/" "/${BACKUP_ROOT}/backup-$SUBJECT-$TIMESTAMP"
		
		# Clear out last backup point
		rm -r $BACKUP_ROOT/$LASTONE-$SUBJECT/*
	   	
		# Make transparent structure	
		cp -al ${BACKUP_ROOT}/backup-$SUBJECT-$TIMESTAMP/* $BACKUP_ROOT/$LASTONE-$SUBJECT
		
		;;
	"make-snap")
		if [ ! -d "${BACKUP_ROOT}" ]; then echo "${BACKUP_ROOT} did not exist; creating it"; mkdir ${BACKUP_ROOT}; fi	
		if [ ! -d "${BACKUP_ROOT}/$LASTONE-$SUBJECT" ]; then echo "${BACKUP_ROOT}/$LASTONE-$SUBJECT did not exist; creating it"; mkdir ${BACKUP_ROOT}/$LASTONE-$SUBJECT; fi
		# Synchronize files
		rsync -av --progress $BACKUP_ROOT/$LASTONE-$SUBJECT "$SUBJECT/" "/${BACKUP_ROOT}/backup-$SUBJECT-$TIMESTAMP"
		
		# Clear out last backup point
		rm -r $BACKUP_ROOT/$LASTONE-$SUBJECT/*
	   	
		# Make transparent structure	
		cp -al ${BACKUP_ROOT}/backup-$SUBJECT-$TIMESTAMP/* $BACKUP_ROOT/$LASTONE-$SUBJECT
		;;
	"remove-old")
		echo "Removing backups from ${BACKUP_ROOT} older than a week"
		#remove older than last week
		#find $BACKUP_ROOT -maxdepth 1 -ctime +6 -print
		find $BACKUP_ROOT -mindepth 1 -maxdepth 1 -ctime +6 -not -name $LASTONE -exec rm -rv {} \;	
		#find $BACKUP_ROOT -not -name $LASTONE -mindepth 1 -maxdepth 1 -print
		;;
	"restore")
		# Restore file copies
		#cp -rv $BACKUP_ROOT/$LASTONE-$SUBJECT/* $SUBJECT/
		rsync -av --progress --delete $BACKUP_ROOT/$LASTONE-$SUBJECT/ $SUBJECT/
		;;
	"list")
		echo "\$BACKUP_ROOT is $BACKUP_ROOT"
		echo -e "Available backups:\n"
		find $BACKUP_ROOT -name "${LASTONE}*" -print
		;;
	"help")
	echo -e "Usage: $0 <make|make-snap|remove-old|restore> <source directory>"
	echo -e "       $0 list"
	echo -e "\tmake - makes a backup in \$BACKUP_ROOT"
	echo -e "\tmake-snap - makes a snapshot backup in \$BACKUP_ROOT"
	echo -e "\tremove-old - removes backups which have change time longer than a week ago"
	echo -e "\trestore - restores a backup"
	echo -e "\tlist - shows last backups"
	echo -e "This script should be run in the directory where the source directory is located"
	echo -e "since it uses <source-directory> parameter as backup name"
		;;

esac