Compress (#1)

README.md

@@ -1,36 +1,42 @@
 # BASH-RaspberryPI-System-Backup
-Bash script for automatic imaging backup of a raspberry pi system while it's running 
-It also cleans out the backups older then the set retention period in days.
-You can have several Raspberry Pi's backup to the same location since it will only clean 
-it's own backups based on $HOSTNAME.
+
+Bash script for automatic imaging backup of a Raspberry Pi system while running.  It also cleans out the backups older than the set retention period in days.
+
+You can have several Raspberry Pi backups in the same location since it will only clean its backups based on `$HOSTNAME`.
 
 ## Install
 
+``` bash
 wget https://github.com/kallsbo/BASH-RaspberryPI-System-Backup/raw/master/system_backup.sh
 chmod +x system_backup.sh
+```
 
 ## Use
 
-In order for the script to work you need either a mounted share or a mounted usb stick.
-Either you can update the defualt values in the script in regards to backup path and retention or
-provide it as command line parameters.
+For the script to work, you need either a mounted share or a mounted USB stick.
 
-Example: sudo ./system_backup.sh /mnt/usbstick 7
+You can update the default values in the script in regards to backup path and retention or provide it as command line parameters.
 
-This will put the backup in /mnt/usbstick and keep the backups for 7 days before cleaning them out.
+Example: `sudo ./system_backup.sh /mnt/usbstick 7`
 
-## Automate
+This will put the backup in `/mnt/usbstick`` and keep the backups for 7 days before cleaning them out.
+
+## Compression
 
-Once you have tested the script and are done with the settings you can automate this bu adding it to 
-crontab. Since it needs to run as root you need to edit the root crontab like this:
+If you desire a compressed image, you may use the optional `-c` flag at the end of your invocation.
+
+Example: `sudo ./system_backup.sh /mnt/usbstick 7 -c`
+
+Compression, especially on a Pi Zero, takes a significantly longer amount of time.
+
+## Automate
 
-sudo crontab -e
+Once you have tested the script and are done with the settings, you can automate this by adding it to `cron`.  Since it needs to run as root, you need to edit the root crontab like this:
 
-I usally go for the default option 2 - nano. Then just add the line
+`sudo crontab -e`
 
-0 3 * * * /mnt/backup/system_backup.sh
+If asked to select an editor, I usually use the default option 2 - nano.  Then add the line:
 
-This will make the script take a full image backup every night at 3 am.
+`0 3 * * * /mnt/backup/system_backup.sh`
 
-## More info
-https://www.hackviking.com/single-board-computers/raspberry-pi/automated-raspberry-pi-backup-complete-image/
+This will make the script take a full image backup every night at 3 a.m.

system_backup.sh

@@ -4,7 +4,7 @@
 #
 # Kristofer Källsbo 2017 www.hackviking.com
 #
-# Usage: system_backup.sh {path} {days of retention}
+# Usage: system_backup.sh {path} {days of retention} {-c to compress}
 #
 # Below you can set the default values if no command line args are sent.
 # The script will name the backup files {$HOSTNAME}.{YYYYmmdd}.img
@@ -15,15 +15,16 @@
 # Declare vars and set standard values
 backup_path=/mnt/backup
 retention_days=3
+compress=0
 
 # Check that we are root!
 if [[ ! $(whoami) =~ "root" ]]; then
-echo ""
-echo "**********************************"
-echo "*** This needs to run as root! ***"
-echo "**********************************"
-echo ""
-exit
+   echo ""
+   echo "**********************************"
+   echo "*** This needs to run as root! ***"
+   echo "**********************************"
+   echo ""
+   exit
 fi
 
 # Check to see if we got command line args
@@ -35,14 +36,26 @@ if [ -n "$2" ]; then
    retention_days=$2
 fi
 
+# Check for compress flag in any arg position
+for var in "$@"
+do
+   if [ "$var" == "-c" ]; then
+      compress=1
+   fi
+done
+
 # Create trigger to force file system consistency check if image is restored
 touch /boot/forcefsck
 
 # Perform backup
-dd if=/dev/mmcblk0 of="$backup_path"/"$HOSTNAME"."$(date +%Y%m%d)".img bs=1M
+if [ "$compress" == 1 ]; then
+   dd bs=1M if=/dev/mmcblk0 | gzip > "$backup_path"/"$HOSTNAME"."$(date +%Y%m%d)".img.gz
+else
+   dd if=/dev/mmcblk0 of="$backup_path"/"$HOSTNAME"."$(date +%Y%m%d)".img bs=1M
+fi
 
 # Remove fsck trigger
 rm /boot/forcefsck
 
 # Delete old backups
-find "$backup_path"/"$HOSTNAME".*.img -mtime +"$retention_days" -type f -delete
+find "$backup_path"/"$HOSTNAME".*.img* -mtime +"$retention_days" -type f -delete