[root@nixos:/]# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.28.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device /dev/sdb already contains a ext4 signature.
The signature will be removed by a write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x9d068c8a.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 3
First sector (2048-250069679, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-250069679, default 250069679): +8G

Created a new partition 3 of type 'Linux' and of size 8 GiB.

Command (m for help): q


[root@nixos:/]#