use `cec-client` to fire events when keys are pressed

cec-keypresses.sh

#!/usr/bin/env bash
#
# react to cec keypresses in the jankiest way possible
#
# Author: Dave Eddy <[email protected]>
# Date: 10/15/2013
# Licens: MIT
# Tested on: Raspberry pi with libcec compiled from soure

onright() {
 	echo 'right button pressed'
}
onleft() {
	echo 'left button pressed'
}
ondown() {
	echo 'down button pressed'
}
onup() {
	echo 'up button pressed'
}
onselect() {
	echo 'select button pressed'
}
onplay() {
	echo 'play button pressed'
}
onpause() {
	echo 'pause button pressed'
}
onforward() {
	echo 'forward button pressed'
}
onbackward() {
	echo 'back button pressed'
}

filter() {
	perl -nle 'BEGIN{$|=1} /key released: (.*) \(.*\)/ && print $1'
}

echo as | cec-client | filter | \
while read cmd; do
	case "$cmd" in
		right) onright;;
		left) onleft;;
		down) ondown;;
		up) onup;;
		select) onselect;;
		play) onplay;;
		pause) onpause;;
		forward) onforward;;
		backward) onbackward;;
		*) echo "unrecognized button ($cmd)";;
	esac
done

install-libcec.md

install libcec on raspbian

sudo apt-get update
sudo apt-get install build-essential autoconf liblockdev1-dev libudev-dev git libtool pkg-config
git clone https://github.com/Pulse-Eight/libcec
cd libcec
./bootstrap
./configure --with-rpi-include-path=/opt/vc/include --with-rpi-lib-path=/opt/vc/lib --enable-rpi
make
sudo make install
sudo ln -s /usr/local/lib/libcec.so /usr/lib/
sudo ln -s /usr/local/lib/libcec.so.2 /usr/lib/

run cec-keypresses.sh

~$ ./cec-keypresses.sh 
right button pressed
right button pressed
left button pressed
up button pressed
down button pressed
select button pressed
select button pressed