http://scott2595.blogspot.com/2014/02/change-size-of-hard-disk-of-virtual.html
2) command to resize a vdi disk
VBoxManage.exe modifyhd ubuntu12_copy.vdi --resize 100000
3) command to clone a vdi disk
http://scott2595.blogspot.com/2014/02/vboxmanagevbox.html
4) command to change the uuid of a vdi disk
VBoxManage.exe internalcommands sethduuid ubuntu12_copy.vdi
5) command to compact a vdi disk
In linux virtual machine:
sudo dd if=/dev/zero of=/bigemptyfile bs=4096k
sudo rm -rf /bigemptyfile
In host:
VBoxManage.exe modifyhd ubuntu12_copy.vdi --compact
