A Linux Backup Script Using The BASH Shell
As mentioned in our previous article about our company backup plan, I’ve provided our simple shell script that backup our information on our server to our external hard drive.
First you need to connect your external hard drive and then mount it. Assuming you’ve done so already, here’s the backup script.
#! /bin/bash
echo Backup Started `date` >> ~/backuplog
mkdir /mnt/usbdrive/backups/`date +%Y%m%d`
tar -czf /mnt/usbdrive/backups/`date +%Y%m%d`/data.tar.gz /data
echo Backup Completed `date` >> ~/backuplog
The first line tells the script that is is using the BASH shell, which is located in /bin/bash on the file server. This is the standard location on nearly any UNIX machine.
The second line tells the script to write a line to a log file (located in our users home directory by specifying the tilde ~ ) with the days date. This log file can be referenced to ensure that the backup is completed each day.
The third line will create the folder on our mounted usbdrive, in the backups folder with the days date in the format YYYYMMDD (example: 20060915).
The fourth line actually creates the backup. On our file server we have created the folder /data where we store everything. We have multiple directories within the data folder for clients, internal documentation, resources, etc… and everything in that folder is compressed into an archive file using the tar command. The file is given the name data.tar.gz.
Finally, the fifth line writes a line to the backuplog telling us that the backup was completed and at what time.
NOTE: You must save this file somewhere on your computer, we recommend in the bin folder of your home directory, and you must give it execute permissions. If you want all users to be able to run the script, you need to use the chmod a+x command, if you want to keep it to yourself, then use the chmod u+x command. S, with it being saved in our home folder’s bin directory we type at the shell terminal:
chmod u+x /home/username/bin/backup
To run the script, simply type: backup from the terminal. Because we placed it in our bin directory (which is in our user’s execute path by default) the system looks there to execute the file. The entire process takes between one and two hours, and using a cronjob we have set this up to run automatically at noon everyday.
00 12 * * 1-5 /home/username/bin/backup
This CRON statement tells the operating system to run the backup command, which is located in the bin directory of the user’s home folder, at 12:00 noon, monday to friday. (We TRY to take weekends off so there isn’t a need for backups).
Now we have a simple script in place that will create a compressed archive of all our sensitive information on a daily basis and store it on our external hard drive.
June 25th, 2008 at 1:56 am
what files does it back up?
or how do i spesify that?
June 25th, 2008 at 8:25 am
This line:
tar -czf /mnt/usbdrive/backups/`date +%Y%m%d`/data.tar.gz /data
tells it to backup the /data directory into a tar file and then move it to /mnt/usbdrive/backups/20080625/data/data.tar.gz where the 20080625 is the current date. Just update /data to whatever folder you want to backup.
June 26th, 2008 at 6:49 am
Thanks for this script!
I’m trying to add some rotation to this code, so that old backups get erased on a regular basis. Do you by any chance know how that could be done?
June 26th, 2008 at 6:54 am
At the beginning of this script I’ve added a few lines that grab the dates of the last 7 days. Then it erases any folder named by those old dates and only keeps the 3 most recent backups. Here it is:
#GET DATE VARIABLES
Today=`date +%Y%m%d`
TwoDaysAgo=`date –date=’2 days ago’ +%Y%m%d`
ThreeDaysAgo=`date –date=’3 days ago’ +%Y%m%d`
FourDaysAgo=`date –date=’4 days ago’ +%Y%m%d`
FiveDaysAgo=`date –date=’5 days ago’ +%Y%m%d`
SixDaysAgo=`date –date=’6 days ago’ +%Y%m%d`
SevenDaysAgo=`date –date=’7 days ago’ +%Y%m%d`
#SETUP PATHS TO OLD BACKUPS
SevenDaysAgoTar=/mnt/usbdrive/backups/$SevenDaysAgo
SixDaysAgoTar=/mnt/usbdrive/backups/$SixDaysAgo
FiveDaysAgoTar=/mnt/usbdrive/backups/$FiveDaysAgo
FourDaysAgoTar=/mnt/usbdrive/backups/$FourDaysAgo
ThreeDaysAgoTar=/mnt/usbdrive/backups/$ThreeDaysAgo
TwoDaysAgoTar=/mnt/usbdrive/backups/$TwoDaysAgo
TodayTar=/mnt/usbdrive/backups/$Today
#DELETE ANY OLD BACKUPS IF THEY EXIST
rm -rf $SevenDaysAgoTar
rm -rf $SixDaysAgoTar
rm -rf $FiveDaysAgoTar
rm -rf $FourDaysAgoTar
You can add / remove the lines from the #DELETE ANY OLD BACKUPS IF THEY EXIST section to automatically delete the folders from those previous days. If they don’t exist then it skips them. Right now, I’m storing the last 3 days.
July 2nd, 2008 at 11:01 am
Thanks Jarrod!
I had the script running for about a week now, and triggered on a daily basis by cron.
But it seems like non of the backups where deleted, not even those older than three days. What may be wrong?
The backuplog returns only the following messages. Do the error messages get stored in another log file?
Backuplog:
Backup Completed Thu Jun 26 17:26:38 CEST 2008
Backup Started Thu Jun 26 17:35:07 CEST 2008
Backup Completed Thu Jun 26 17:35:41 CEST 2008
Backup Started Fri Jun 27 11:26:01 CEST 2008
Backup Completed Fri Jun 27 11:27:26 CEST 2008
Backup Started Sat Jun 28 11:26:01 CEST 2008
Backup Completed Sat Jun 28 11:27:22 CEST 2008
Backup Started Sun Jun 29 11:26:01 CEST 2008
Backup Completed Sun Jun 29 11:27:32 CEST 2008
Backup Started Mon Jun 30 11:26:02 CEST 2008
Backup Completed Mon Jun 30 11:27:59 CEST 2008
Backup Started Tue Jul 1 11:26:01 CEST 2008
Backup Completed Tue Jul 1 11:27:43 CEST 2008
Backup Started Wed Jul 2 11:26:01 CEST 2008
Backup Completed Wed Jul 2 11:27:28 CEST 2008
July 2nd, 2008 at 11:11 am
The only thing I can think of off the top of my head is either the paths have a typo in them so the command to delete them is not working, or a permissions issue.
July 20th, 2008 at 3:37 am
Thanks much Jarrod!
Can you show us also your restore script that will restore the backup to its original location?
August 18th, 2008 at 6:50 am
Very helpful, thanks much!
September 17th, 2008 at 1:03 pm
Great guide. I modified it some, and made a simple backup script out of it:
#! /bin/bash
# Variables
location=/home/veiset
directory=Documents
backuplocation=/media/veiset/backup
log=~/backup.log
echo -e “\nBackup started: `date`” >> $log
if [ -d $backuplocation ]; then
mkdir -p $backuplocation/`date +%y%m%d`
cd $location
tar -cvvf $backuplocation/`date +%y%m%d`/data.`date +%H%M%S`.tar.gz $directory
echo ” completed: `date`” >> $log
cp $log $backuplocation/backup.log
echo -e “\n — Backup completed –\n”;
else
echo ” FAILED: `date`” >> $log
echo -e “\n– WARNING: –”
echo -e “– BACKUP FAILED –\n”;
fi
The script now checks if the backup was successful. There are also variables that are defined so its easier to edit the locations of the backup locations.
‘location’ is the location of the folder ‘directory’, which will be taken backup of. ‘backuplocation’ is where the backup is saved. :)
October 13th, 2008 at 4:58 am
The only output appended to ~/backuplog is the standard output of date.
Any errors (or any other output) should be sent to your mail box.
If instead you wanted the errors to appear in the log then you would want to delete the `>> ~/backuplog’ from the script and your cron line should read:
00 12 * * 1-5 /home/username/bin/backup >> ~/backuplog 2>&1
I haven’t tested this though so you shouldn’t follow these instructions blindly. Employ critical thinking.
March 15th, 2009 at 11:25 pm
Nice job! Very useful tutorial for freshers! Thank you.
April 19th, 2009 at 11:54 pm
To get the dates of the last 7 days.Correct syntax as
Today=`date +%d-%m-%Y`
TwoDaysAgo=`(date –date=’2 days ago’ ‘+%d-%m-%Y’)`
ThreeDaysAgo=`(date –date=’3 days ago’ ‘+%d-%m-%Y’)`
FourDaysAgo=`(date –date=’4 days ago’ ‘+%d-%m-%Y’)`
FiveDaysAgo=`(date –date=’5 days ago’ ‘+%d-%m-%Y’)`
SixDaysAgo=`(date –date=’6 days ago’ ‘+%d-%m-%Y’)`
SevenDaysAgo=`(date –date=’7 days ago’ ‘+%d-%m-%Y’)`
April 21st, 2009 at 5:29 pm
Hi, i’m just wondering how to make the script that there’s a choice between full backup, incremental backup, and differential backup.. either it’s compressed or uncompressed as well. thanks
May 23rd, 2009 at 7:49 pm
hey dude i was wondering if there is a way to write a script to back up a given set of directories which can be easily automated to run at a particular time.
ie. user inputs which DIRS to backup ….
can u give me the code please ?
June 6th, 2009 at 3:42 am
In the above script:
TwoDaysAgo=`date –date=’2 days ago’ +%Y%m%d`
there’s a typo. It should say:
TwoDaysAgo=`date –date=’7 days ago’ +%Y%m%d`
That’s probably why it didn’t work for Peter.
June 6th, 2009 at 3:48 am
Huh… it seems like when you post the comment double dash is changed to single dash.
After TwoDaysAgo=`date there should be two dashes.
July 1st, 2009 at 10:15 pm
Hi, I am newbie and I found this working great in my Linux machine. But I am curious, if I don’t wanna tar the backup folder/files, how should I change this line:
tar -cvvf $backuplocation/`date +%y%m%d`/data.`date +%H%M%S`.tar.gz $directory
I try remove the tar but it not working =)
Your help are great appreciated, thank you.
July 1st, 2009 at 11:13 pm
I got it like this:
cp -i -p -R $location/$directory $backuplocation/`date +%y%m%d`/data.`date +%H%M%S`
thanks