Remove old backups with Bash Shell

Hello folks, I present you a bash script I wrote recently. It’s purpose  is deleting ‘old’ directories  marked by time period expressed in days. The script is simple and at its bases uses the command find to locate directories that we want to remove.

The general thinking on which this script is based are directories with backups categorized by some logical distinction and retention period for the second level of directories that are sorted by some other means like let’s say date. The script run by cron job searches the second level of directories and deletes the one older than some number of days n.

Example structure:

/mnt/backup/apps/2014-06-20/*

/mnt/backup/dbs/2014-06-1/*

/mnt/backup/logs/2014-06-1/*

 

If we want to exclude some of the directories in /mnt/backup , for example /mnt/backup/logs we can do that by putting the path into the variable EXCLUDED_DIRS. Note that only the directories from depth 1 can be excluded with this implementation (/mnt/backup/<> = OK , /mnt/backup/logs/<> != OK ).

EXCLUDED_DIRS=”/mnt/backup/logs /some/other/etc”

 

USAGE of the script:

<script_name> {arg1:/path/to/folder} {arg2:n days}  

or

./deleteOldDirs.sh         /mnt/backup           60

 

Note on find. For checking the timestamp of the directory I use ctime like option from find.  When this argument is used ,  find checks for the iNode pointing to the file/folder and collects information (like permissions, owner, etc) from which can be determinated when it was modified. In other hand if we want to check modification of the data in the backup itself we can use the argument mtime instead.

 

The script , beware of removing yourself.

May the force be with you !

#!/bin/bash

#
# GNRP LICENSE: Script licensed by GOD
#
# @author: Igor Ivanovski <igor at genrepsoft.net>
#
# July, 2014
#

#
# *** VARIABLES
#

PATH=$1 # First argument should be PATH of the backup folder
DAYS=$2 # Secound argument should be the max number of days we want to keep backups

GREP="/bin/grep"
MOUNT="/bin/mount"
FIND="/usr/bin/find"
RM="/bin/rm"

PATH_STATUS=0
MOUNT_STATUS=0

EXCLUDED_DIRS="/home/igor/Documents /home/igor/Programs"

#
# *** CHECKERS
#

if [ $# -eq 0 ]; then
    echo "No arguments provided"
    exit 1
fi

if [ -z $PATH ] || [ -z $DAYS ]; then
    echo "Not all arguments provided"
    exit 1
fi

#
# *** FUNCTIONS
#

function check_if_path_exists {

	[ ! -d $1 ] && echo "Path is invalild" || PATH_STATUS=1
}

function check_mount {
	 if [ -n "$($GREP $1 /etc/fstab)" ]; then
                echo "Mounting point exists..."
		if [ ! -n "$($MOUNT -l | $GREP $1)" ]; then
		    echo "...but not mounted."
		    echo "Mounting now."
                    $MOUNT $1
                    [ $? -eq 0 ] && { echo "Mounting was successfull!"; MOUNT_STATUS=1; } || echo "Can't mount";
		fi
         else
                echo "Mounting point doesn't exist"
         fi
}

# Excludes only if parent directory fits
function check_if_parent_dir_excluded { 
            for dir in $EXCLUDED_DIRS; do
		size=${#dir}
	        check=${1:0:size}
		#echo "$dir : ${#dir} == $check : ${#check}"
		if [ $dir ==  $check ]; then 
			echo "1"
		fi
	    done
}

function find_dirs {
	$FIND $PATH -mindepth 2 -maxdepth 2 -type d -ctime +$DAYS -print0
}

function print_dirs {
	while read -r n; do
                 result=$(check_if_parent_dir_excluded $n)
		 [ -z $result ] && printf '%q\n' "$n" || echo "Found EXCLUDE_DIR: $n" 
	done < <($FIND $PATH -mindepth 2 -maxdepth 2 -type d -ctime +$DAYS -print) # Use NL delimiter
}

function del_dirs {
        while read -r -d '' n; do
                 printf '%q\n' "$n"
                 result=$(check_if_parent_dir_excluded $n)
                 if [ -z $result ]; then
			 echo "Directory will be deleted now..."
			 $RM -rf $n
			 [ $? -eq 0 ] && echo "Gone!" || echo "Some error occured!"
		 else	
	 		echo "Found EXCLUDE_DIR: $n continue..." 
		 fi
        done < <($FIND $PATH -mindepth 2 -maxdepth 2 -type d -ctime +$DAYS -print0) # Use NUL delimiter
}

#
# *** MAIN
#

check_if_path_exists $PATH
[ $PATH_STATUS -eq 0 ] && check_mount $PATH
[ $MOUNT_STATUS -eq 1 ] && check_if_path_exists $PATH
[ $PATH_STATUS -eq 1 ] &&  del_dirs || { echo "Bye."; exit 0; }

#
# *** END
#