Simple Sharing with Samba on Raspbian

Install Samba

sudo apt-get update
sudo apt-get install samba samba-common-bin

Add a new section to the end of /etc/samba/smb.conf.

[backup]
    comment = Ubuntu File Server Share
    path = <SHARE_DIRECTORY>
    writeable = yes
    guest ok = yes

Change the username of the share to nobody, and change the group of the share to nogroup.

cd <SHARE_DIRECTORY>
chown -R nobody.nogroup *