A bash script for distributed, encrypted, recurring backups

[matzus]

Hi everybody,

I wrote a fairly simple bash script that creates encrypted backups of any given file or directory. The script will delete old backup sets and should be run daily as a cronjob. It requires that rsync be installed.

Please feel free to use, modify and share the code. I am also looking forward to suggestions on how to improve the script.

Here it is:

Code: Select all

#!/bin/bash

###########################################
###					###
###	(c) 2016 by Matthias Ewering	###
###					###
###	 matthias.ewering@posteo.de	###
###					###
###	!! No warranty whatsoever !!	###
###					###
###########################################

source=/path/to/source	#The element to be backed up
daily=/path/to/backup/daily	#The directory that will contain the daily backup files
weekly=/path/to/backup/weekly	#The directory that will contain the weekly backup files
monthly=/path/to/backup/monthly	#The directory that will contain the monthly backup files
main=/path/to/backup	#The main backup directory for all backup cycles
mirror1=/path/to/backup_mirror1	#The first mirror of the main backup directory
mirror2=/path/to/backup_mirror2	#The second mirror of the main backup directory
#mirrorn=/foo/bar	#The n^th mirror of the main backup directory

tar -czPf ./$(date +"%Y-%m-%d_%H-%M")_backup.tar.gz "$source"	#Create a compressed tarball with the contents to be backed up

gpg --symmetric --cipher-algo aes256 --passphrase secret -o ./$(date +"%Y-%m-%d_%H-%M")_backup.tar.gz.gpg ./*_backup.*	#Encrypt the tarball. Remember to replace "secret" with A CUSTOM, SECURE PASSPHRASE!

mv ./*.gpg "$daily"	#Move the encrypted backup file to the main daily backup directory

rm ./*_backup.*	#Delete the unencrypted tarball

find "$daily" -type f | sort -rd | sed -e '1,7d' | xargs -d '\n' rm --	#Delete any file from the main daily backup directory with the 8th oldest timestamp or older

if [ $(date +"%u") = "7" ]

	then 	find "$daily" -type f | sort -d | sed -e '1,6d' | xargs cp -t "$weekly"
											#On a Sunday, copy the latest daily backup file to the weekly backup directory,... 
		find "$weekly" -type f | sort -rd | sed -e '1,5d' | xargs -d '\n' rm --	#...then delete any file from the weekly backup directory with the 6th oldest...
											#...timestamp or older
fi

if [ $(find "$daily" -type f | sort -rd | awk -F '/' '{print $NF}' | cut -c1-4 | head -2 | tail -1) -lt $(date +"%Y") ]
                                                                                                                #When a new year has begun, create an archive directory for...
        then    mkdir "$main"/$(($(date +"%Y") - 1))                                                            #...the old year and move the monthly files to that archive directory

                mv "$monthly"/*.gpg "$main"/$(($(date +"%Y") - 1))

fi

if [ $(date +"%d") = "01" ]
											#On the first of a month, copy the latest daily backup file to the monthly backup directory
	then 	find "$daily" -type f | sort -d | sed -e '1,6d' | xargs cp -t "$monthly"

fi

rsync -a --delete "$main" "$mirror1"	#Synchronize the first mirror directory with the main backup directory

rsync -a --delete "$main" "$mirror2"	#Synchronize the second mirror directory with the main backup directory

#rsync -a --delete "$main" "$mirrorn"	#Synchronize the n^th mirror directory with the main backup directory

exit 0

edit: corrected a sorting error.