create new partition on hard drive in command line

Create partition
fdisk /dev/devname

in menu, key: n
write changes, key: w
and exit, key: q

Create file system
mkfs.ext4 /dev/devnameX

fdisk /dev/sda
Command (m for help): m

short keys review:

Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition’s system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)

Command (m for help): a
Partition number (1-5):