WiringPi: An implementation of most of the Arduino Wiring functions for the Raspberry Pi
WiringPiGem: The WiringPi library wrapped up for Ruby with some OO goodness, sanity checking and other handy additions.
require 'wiringpi'
io = WiringPi::GPIO.new
io.write(pin,value)
io.read(pin,value)
io.write(latch_pin, LOW)
io.shiftOut(data_pin, clock_pin, LSBFIRST or MSBFIRST, value)
io.write(latch_pin, HIGH)
Shift out an array of 1/0s (always uses LSBFIRST):
io.shiftOutArray(data_pin, clock_pin, latch_pin, [0,1,0,0,1,1,1,0])
require 'wiringpi'
io = WiringPi::GPIO.new(WPI_MODE_SYS)
# read/write/shift as usual
require 'wiringpi'
s = WiringPi::Serial.new('/dev/ttyAMA0',9600)
s.serialPuts('Hello world!')
s.serialClose
Full details at: https://projects.drogon.net/raspberry-pi/wiringpi/