PARANOIDIX

#!/bin/bash
###############################################################################
# Script to make a backup of files using rsync.
# It rotates directories automatically.
#
# To ensure the backupdrive is mounted, the script checks for the existance of 
# a file named 'mount_OK' (without the quotes)
#
# Copyright 2014 Rene Rasmussen
#
# Published under the MIT license. 
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy 
# of this software and associated documentation files (the "Software"), 
# to deal in the Software without restriction, including without limitation 
# the rights to use, copy, modify, merge, publish, distribute, sublicense, 
# and/or sell copies of the Software, and to permit persons to whom the 
# Software is furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included 
# in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 
# IN THE SOFTWARE.
#
###############################################################################

# Backup drive mountpoint
backup_drive="/mnt/backer"

# Parent backup directory
backup_parent_dir="${backup_drive}/homeback"

# Number of backups
# (number of directories in rotation)
# count starts from 0, so below value defines directories+1
backup_dir_count=12

#initialize errors variable
errors=0

# Check if drive is mounted
# (check for mount_OK file)
okFile=${backup_drive}/mount_OK
if [ -f $okFile ]
then
   # If the destination folder does not exist, it will be created
   if [ ! -d $backup_parent_dir ]
   then
      mkdir -p $backup_parent_dir
      chmod 750 $backup_parent_dir
   fi
   # Rotate backup directories
   for (( c=$backup_dir_count; c>=2; c-- ))
   do
      if [ $c -eq $backup_dir_count ]
      then
         dirPath=${backup_parent_dir}/backup$c
         #echo "0 = $dirPath" #debug
         if [ -d $dirPath ]
         then
            rm -rf $dirPath
         fi
      fi
         dirPath1=${backup_parent_dir}/backup$((c-1))
         dirPath2=${backup_parent_dir}/backup$c
         #echo "1 = $dirPath1" #debug
         #echo "2 = $dirPath2" #debug
         if [ -d $dirPath1 ]
         then
            mv $dirPath1 $dirPath2
         fi
   done
   # copy contents from backup0 to backup1 with hardlinks
   dirPath1=${backup_parent_dir}/backup0
   dirPath2=${backup_parent_dir}/backup1
   if [ -d $dirPath1 ]
   then
      cp -al $dirPath1 $dirPath2
   fi
   # remove old datestamp file from rsync destination
   if test -n "$(find $dirPath1 -maxdepth 1 -name 'MyBackup*' -print -quit)"
   then
      rm $dirPath1/MyBackup*
   fi
   # sync files to backupfolder
   rsync -aq --delete /home $dirPath1
   # create datestamp (empty) file
   touch $dirPath1/"MyBackup from $(date '+%A, %d %B %Y, %T')"
else
   errors=1
fi

# Error handling
if [ $errors != 0 ]
then
   # Select error message based on errors value   
   # errors = 1 => Backup drive not mounted
   fdesc="ERROR with backup"
   case $errors in
      1)
         fbody="Backup location not accessible! Please investigate cause!"
         ;;
      *)
         fbody="Something went wrong. Please investigate!"
         ;;
   esac
   # Error message for screen
   echo $fdesc
   echo $fbody

   ## error email for admin
   receiver="admin@example.com"

   echo $fbody | mail -s "$fdesc" $receiver

   exit
fi

## rsync options
# The option -n can be used to make a dry-run

# The option -P shows the progress

## Description of option switches
# Option -C => CVS exclude
# Option -v => Verbose
# Option -r => Rercursive
# Option -t => Times
# Option -p => Permissions


# An alternative to the above options is option -a
# Option -a => -rlptgoD

# Option -r => Rercursive
# Option -l => links
# Option -p => Permissions
# Option -t => Times
# Option -g => Group
# Option -o => Owner
# Option -D => devices & specials