How can you start fdisk interactively for a specific disk?

To start fdisk interactively for a specific disk, you would use the following command in the terminal:

sudo fdisk /dev/sdX

Replace X with the appropriate letter corresponding to the disk you want to partition (e.g., a, b, c, etc.). For example, if you want to work with the first disk, you would use:

sudo fdisk /dev/sda

This command will open the fdisk utility for the specified disk, allowing you to create, delete, or modify partitions interactively.