root@ubuntu-mate:/#  sudo fdisk /dev/sdf
sudo: unable to resolve host ubuntu-mate: No such file or directory

Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help): o
Created a new DOS disklabel with disk identifier 0x3c463b7e.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.