Reclaim free space from Time Machine sparsebundle

You msut run these commands as root:

sudo su - 

Make sure the mount point exists:

mkdir -p /Volumes/TM

Then mount the afp share:

mount_afp 'afp://user:password@afp_server_address/share_name' /Volumes/TM

Now use hdiutil to reclaim the available free space:

hdiutil compact /Volumes/TM/ComputerName.sparsebundle/

unmont the share:

umount /Volumes/TM/

If you get an error message saying:

hdiutil: compact failed - Resource temporarily unavailable

You must make sure you don't have the afp share mounted elsewhere, you can check your mounts with:

df -h

If the output contains a line with your afp server's address or with the string "Time Machine" you have to unmount them.

The following script will do all that for you:

SRV="afp_server_address"
SAVEIFS=$IFS
IFS=$'\n';
for v in $(df -h | grep -E "$SRV|Time\sMachine"  | cut -d"%" -f3 |  sed -e "s/ *\//\//"); do
    umount "$v"
done
IFS=$SAVEIFS
mkdir -p /Volumes/TM
mount_afp "afp://user:password@$SRV/share" /Volumes/TM
hdiutil compact "/Volumes/TM/$(scutil --get ComputerName).sparsebundle"
umount /Volumes/TM/