1. U disk into pie raspberry, input
sudo fdisk -l
displayed Disk / dev / sda: xx Gib , xx bytes, and the xxxx match keys to disk capacity U
2. Mount
new directory (mount manual, will not automatically mount the new media directory)
the sudo mkdir / mnt / usb_flash
and mount devices
sudo mount / dev / sda1 / mnt / usb_flash /
3. need to pull out the U disk
sudo umount / mnt / usb_flash
or
sudo umount / dev / sda1