I want to connect my raspberry pi to wi-fi and this wi-fi uses ip address. I use raspberry pi model 2 (B+), I have wi-fi dongle. How do I connect? I have connected to pi using ssh, and I'm only able to access the command line of pi and don't have access to it's GUI.
EDIT::
>> cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 8 (jessie)"
NAME="Raspbian GNU/Linux"
VERSION_ID="8"
VERSION="8 (jessie)"
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"