Setup Raspberry Pi from scratch

sudo apt-get install tree

To find the SD Card for you Raspberry Pi, Insert it into your computer and type:

lsblk

Assuming that you only have one similarly sized device inserted at this time it should be fairly easy to figure out which device you want based on size. If your using a Linux distro like Ubuntu, it will automaticly mount your SD Card, and you don't want that so umount it with:

sudo umount /dev/<device number>

Repeat this command adjusting the device number until all partitions are unmounted.

Next, we need to repartition the SD card with fdisk.

sudo fdisk /dev/<device number>

Delete all partitions using 'd'
Create a new partition using 'c'
Use the default options for everything except the endpoint (if the sd card is over 16g...use +8G for the endpoint)
Set partition with 't' and set to type 'b' (FAT 32)
Set bootable with 'a'
Write changes with 'w'

Create a new filesystem on the SD card. (format it)

sudo mkfs.vfat /dev/<device number>

Next I create a directory that I use for temporarily mounting devices:

sudo mkdir /media/temp

Mount the newly formatted SD Card:

sudo mount /dev/<device number> /media/temp/