i've to install a number of machines. Some machines have windows 7 installed. Some machines not. The machines have 0 or 2 or 3 partitions. Every machine has enough free diskspace (20 to 250 GB)

I installed an "golden client" and build an tar archiv of this client. Now, every client boots up a small linux via pxe, and run a script. This script should create a ext4 and a swap partition using the whole free space. After this, mount the ext4-partition, copy tar, chroot, and so on.

The problem still is: I can create partitions using fdisk. But how can i figure out the partion number of the new partition. Do i have to mount /dev/sda3 or /dev/sda1? Someone an idea?

Further question: How can i figure out, if the is unallocated space, and how much it is?

Thanks