Creating new disk partitions

Now let's play with the new disk that we just created. The first thing you may want to do is to create a new partition. To create a new partition, we use the fdisk command followed by the disk name:

fdisk [options] device

So to create a new partition on the /dev/sdb disk; you can run the following command:

root@ubuntu-linux:~# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.31.1).
Changes will remain in memory only, until you decide to write them. 
Be careful before using the write command.

Device does not contain a recognized partition table. 
Created a new DOS disklabel with disk identifier 0xb13d9b6a.

Command (m for help):

This opens up the fdisk utility. If you are unsure what to do; you can enter m for help:

Command (m for help): m 
Help:
  DOS (MBR)
  a   toggle a bootable flag
  b   edit nested BSD disklabel
  c   toggle the dos compatibility flag

  Generic
  d   delete a partition
  F   list free unpartitioned space l list known partition types
  n   add a new...