backup to sdhc

backuptosdhc.sh

#!/bin/sh

# A script that first checks if an external disk is mounted and
# then uses rsync to perform a time machine style backup.
#
# I need to work on the how the script behaves when the disk is 
# full. Ideally, it would delete the oldest backup.
#

original="/"
uuid="FEBD96D7-1F10-3D49-BA02-9D482B6839C8"

date=`date "+%Y-%m-%dT%H-%M-%S"`

data=`diskutil info $uuid`

# Verify that the disk is mounted

if echo $data | grep "Could not find disk"; then 
	echo "Backup Disk not Mounted."
	exit
fi

# Determine mount point (path) of disk

diskpath=`echo "$data" | grep "Mount Point:" | perl -pe "s|.*?/|/|"`
destination="$diskpath/Backups"

# Check for free space

freespace=`echo "$data" | grep "Free Space:"` | perl -pe "s/.*\((\d+).* Bytes.*/\1/"

if [ $freespace < 10000 ]; then
	echo "Disk almost full! I will try deleting the oldest backup."
	echo "Autodeletion has not been tested"
	echo "To try it, please edit the script..."	
	oldest="$destination/"`ls -t "$destination" | grep back | head -1`
	echo "If allowed, the script would delete $oldest."
#	rm -rf "$oldest"
	echo "Then it would try to run itself again."
#	$0
	exit
fi


rsync -aP \
	--delete \
	--delete-excluded \
	--exclude-from=/Users/david/.rsync/exclude-sdhc \
	--link-dest="$destination/current" "$original" "$destination/back-$date" \
&& rm -f "$destination/current" \
&& ln -s "$destination/back-$date" "$destination/current"