OpenWRT rc.local for advertising block

rc.local

# Put your custom commands here that should be executed once
# the system init finished. By default this file does nothing.
# http://paul.is-a-geek.org/2015/06/dns-based-adblock-using-openwrt-opendns-and-dnsmasq/

#!/bin/sh
#Block ads, malware, etc.
logger -t "adblock" -s 'Starting adblock setup...'

#Delete the old adblock_hosts to make room for the updates
rm /tmp/adblock_hosts

logger -t "adblock" -s 'Downloading hosts lists...'
wget -qO- "http://winhelp2002.mvps.org/hosts.txt" | awk '/^0.0.0.0/' > /tmp/block.build.list
wget -qO- "http://www.malwaredomainlist.com/hostslist/hosts.txt" | awk '{sub(/^127.0.0.1/, "0.0.0.0")} /^0.0.0.0/' >> /tmp/block.build.list
wget -qO- "http://hosts-file.net/ad_servers.txt" | awk '{sub(/^127.0.0.1/, "0.0.0.0")} /^0.0.0.0/' >> /tmp/block.build.list
wget -qO- "http://adaway.org/hosts.txt" | awk '{sub(/^127.0.0.1/, "0.0.0.0")} /^0.0.0.0/' >> /tmp/block.build.list

if [ -s "/etc/black.list" ]
then
 logger -t "adblock" -s 'Adding blacklist...'
 awk '/^[^#]/ { print "0.0.0.0",$1 }' /etc/black.list >> /tmp/block.build.list
fi

logger -t "adblock" -s 'Sorting lists...'
awk '{sub(/\r$/,"");print $1,$2}' /tmp/block.build.list|sort -u > /tmp/block.build.before

if [ -s "/etc/white.list" ]
then
 #Filter the blacklist, supressing whitelist matches
 # This is relatively slow =-(
 logger -t "adblock" -s 'Filtering white list...'
 awk '/^[^#]/ {sub(/\r$/,"");print $1}' /etc/white.list | grep -vf - /tmp/block.build.before > /tmp/adblock_hosts
else
 cat /tmp/block.build.before > /tmp/adblock_hosts
fi

logger -t "adblock" -s 'Cleaning up...'

#Delete files used to build list to free up the limited space
rm -f /tmp/block.build.before
rm -f /tmp/block.build.list

logger -t "adblock" -s 'Restarting dnsmasq...'
/etc/init.d/dnsmasq restart

logger -t "adblock" -s 'Finished adblock setup'

exit 0