ip-flash

#!/bin/bash
#
# ip-flash :: flash the IP address on led0 (or the specified LED) of a system
#
# 1 - 9 short flashes indicate the digits 1 - 9
# 10 short flashes indicate the digit 0
# a long flash indicates an octet separator (dot)
# a brief pause separates digits
#
# Arguments:
# $1 - directory for LED control (default /sys/class/leds/led0)
#
# Note: This script requires trigger control of the specified LED - the kernel
# must provide the none and default-on targets for the LED trigger, and
# this script must be executed with appropriate privilege (root by default).
#
# The default LED is valid for the Raspberry Pi and some other development
# boards.
#
# 0.1 - Chris Tyler, Seneca College <chris.tyler@senecacollege.ca> 2012-07-17
# 0.2 - Chris Tyler, Seneca College <chris.tyler@senecacollege.ca> 2013-03-26
#

#    ip-info
#
#    Copyright (C)2012 Chris Tyler, Seneca College, and others (see above)
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
#    MA  02110-1301  USA
#

# Control directory for the LED
CTL=${1:-/sys/class/leds/led0}

# IP address (first IPv4 address that is not loopback)
if [ -x /usr/sbin/ip ]
then
        IP=$(ip addr|sed -n "s/^[[:space:]]\+inet \([0-9.]\+\).*/\1/p"|
                grep -v 127.0.0.1|head -1)
elif [ -x /usr/bin/ifconfig ]
then
        IP=$(ifconfig|sed -n "s/.*inet [^0-9]*\([0-9.]\+\) .*/\1/p"|
                grep -v 127.0.0.1|head -1)
else
        echo "$0: Cannot determine IP address - /usr/sbin/{ip,ifconfig} missing" >&2
        exit 1
fi

if [ "$IP" = "" ]
then
        echo "$0: No IPv4 address found." >&2
        exit 2
fi

# Flash on designated LED
if cd ${CTL} >/dev/null 2>&1
then
	SAVE=$(sed "s/.*\[\(.*\)\].*/\1/" trigger) # Save LED trigger state

	for REPEAT in 1 2
	do


		echo none > trigger
		sleep 4
		 
		for ((x=0; x<${#IP}; x++))
		do
			DIGIT=${IP:$x:1}
			if [[ "$DIGIT" = "." ]]
			then 
				echo default-on > trigger
				echo 255 > brightness
				sleep 1.5
				echo none > trigger
				sleep 1.5
			else
				if [[ "$DIGIT" = 0 ]]
				then
					DIGIT=10
				fi
				for ((y=0; y<DIGIT; y++))
				do
					echo default-on >trigger
					sleep 0.25
					echo none > trigger
					sleep 0.25
				done
				sleep 1.5
			fi
		done
		sleep 4
		echo $SAVE > trigger
	done

else
	echo "$0: LED control directory $CTL does not exist." >&2
	exit 3
fi