Light LED in Raspberry Pi

Command:

1login as root: su - root
2connect gpio 17 pin and GND pin
3echo 17 > /sys/class/gpio/export
4echo out > /sys/class/gpio/direction
5echo 1 > /sys/class/gpio/value # LED bright
6echo 0 > /sys/class/gpio/value # LED dim
7echo 17 > /sys/class/gpio/unexport

WiringPi

1gpio mode 0 out
2gpio write 0 1
3gpio write 0 0

WiringPi-python

1sudo get-apt install python-dev python-pip
2sudo pip install wiringpi
3or 
4sudo esay_install-2.7 wiringpi
5blink.py
6import wiringpi
7io = wiringpi.GPIO(wiringpi.WPI_MODE_SYS)  
8io.pinMode(17,io.OUTPUT)
9io.digitalWrite(18,io.HIGH)  # Turn on light
10io.digitalWrite(18,io.LOW)  # Turn off

Reference
https://github.com/Gadgetoid/WiringPi2-Python
http://wiringpi.com/