diff --git a/gravity-adv.sh b/gravity-adv.sh
index 3250811b..eef65190 100755
--- a/gravity-adv.sh
+++ b/gravity-adv.sh
@@ -6,12 +6,19 @@ piholeIP="127.0.0.1"
 #piholeIP=$(hostname -I)
 
 # Config file to hold URL rules
-eventHorizion="/etc/dnsmasq.d/adList.conf"
+eventHorizon="/etc/dnsmasq.d/adList.conf"
 piholeDir='/etc/pihole/'     
 
 blacklist=$piholeDir'blacklist.txt'
 whitelist=$piholeDir'whitelist.txt'
 
+tmpDir='./tmp/'    
+tmpAdPrefix=$tmpDir'matter.pihole'
+tmpAdList=$tmpAdPrefix'.txt'
+tmpConf=$tmpDir'andLight.pihole.txt'
+tmpWhiteList=$tmpDir'yang.pihole.txt'
+tmpBlackList=$tmpDir'yin.pihole.txt'
+
 # Create the pihole resource directory if it doesn't exist.  Future files will be stored here
 if [[ -d $piholeDir ]];then
 	:
@@ -20,64 +27,90 @@ else
 	sudo mkdir $piholeDir
 fi
 
-tmpDir='/tmp/'    
-tmpAdList=$tmpDir'matter.pihole.txt'
-tmpConf=$tmpDir'andLight.pihole.txt'
-tmpWhiteList=$tmpDir'yang.pihole.txt'
-tmpBlackList=$tmpDir'yin.pihole.txt'
+#if pipe is not empty write it into file $1
+writeifne () {
+        read pipe || return 1
+        { printf "%s\n" "$pipe"; cat; }  > "$1"
+}
 
 echo "Getting yoyo ad list..." # Approximately 2452 domains at the time of writing
-curl -s -d mimetype=plaintext -d hostformat=unixhosts http://pgl.yoyo.org/adservers/serverlist.php? | sort > $tmpAdList
+curl -s -d mimetype=plaintext -d hostformat=unixhosts http://pgl.yoyo.org/adservers/serverlist.php?  -z $tmpAdPrefix."yoyo.txt" -o $tmpAdPrefix."yoyo.txt"
 echo "Getting winhelp2002 ad list..." # 12985 domains
-curl -s http://winhelp2002.mvps.org/hosts.txt | grep -v "#" | grep -v "127.0.0.1" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' >> $tmpAdList
+curl -s http://winhelp2002.mvps.org/hosts.txt -z $tmpAdPrefix."winhelp2002.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | sed $'s/\r$//' | writeifne $tmpAdPrefix."winhelp2002.txt"
 echo "Getting adaway ad list..." # 445 domains
-curl -s https://adaway.org/hosts.txt | grep -v "#" | grep -v "::1" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' >> $tmpAdList
+curl -s https://adaway.org/hosts.txt -z $tmpAdPrefix."adaway.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | writeifne $tmpAdPrefix."adaway.txt"
 echo "Getting hosts-file ad list..." # 28050 domains
-curl -s http://hosts-file.net/.%5Cad_servers.txt | grep -v "#" | grep -v "::1" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' >> $tmpAdList
+curl -s http://hosts-file.net/.%5Cad_servers.txt -z $tmpAdPrefix."hosts-file.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | sed $'s/\r$//' | writeifne $tmpAdPrefix."hosts-file.txt"
 echo "Getting malwaredomainlist ad list..." # 1352 domains
-curl -s http://www.malwaredomainlist.com/hostslist/hosts.txt | grep -v "#" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $3}' | grep -v '^\\' | grep -v '\\$'  >> $tmpAdList
+curl -s http://www.malwaredomainlist.com/hostslist/hosts.txt -z $tmpAdPrefix."malwaredomainlist.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | sed $'s/\r$//' | writeifne $tmpAdPrefix."malwaredomainlist.txt"
 echo "Getting adblock.gjtech ad list..." # 696 domains
-curl -s http://adblock.gjtech.net/?format=unix-hosts | grep -v "#" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' >> $tmpAdList
+curl -s http://adblock.gjtech.net/?format=unix-hosts -z $tmpAdPrefix."gjtech.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | sed $'s/\r$//' | writeifne $tmpAdPrefix."gjtech.txt"
 echo "Getting someone who cares ad list..." # 10600
-curl -s http://someonewhocares.org/hosts/hosts | grep -v "#" | sed '/^$/d' | sed 's/\ /\\ /g' | grep -v '^\\' | grep -v '\\$' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' >> $tmpAdList
+curl -s http://someonewhocares.org/hosts/hosts -z $tmpAdPrefix."someonewhocares.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | sed $'s/\r$//' | writeifne $tmpAdPrefix."someonewhocares.txt"
 echo "Getting Mother of All Ad Blocks list..." # 102168 domains!! Thanks Kacy
-curl -A 'Mozilla/5.0 (X11; Linux x86_64; rv:30.0) Gecko/20100101 Firefox/30.0' -e http://forum.xda-developers.com/ http://adblock.mahakala.is/ | grep -v "#" | awk '{print $2}' >> $tmpAdList
+curl -A 'Mozilla/5.0 (X11; Linux x86_64; rv:30.0) Gecko/20100101 Firefox/30.0' -e http://forum.xda-developers.com/ http://adblock.mahakala.is/ -z $tmpAdPrefix."mahakala.txt" | awk '/^[0-9]{1,3}(\.[0-9]{1,3}){3}/ {print $2}' | sed $'s/\r$//' | writeifne $tmpAdPrefix."mahakala.txt"
 
-# Add entries from the local blacklist file if it exists in $piholeDir directory
-echo -n "" > $tmpBlackList
-if [[ -f $blacklist ]];then
+# Merge temporary files. Remove lines with no dots (i.e. localhost, localdomain, etc)
+echo -n "" > $tmpAdList
+for i in $tmpAdPrefix.*.txt
+do
+    grep '\.' $i >> $tmpAdList
+done
+
+# If newer, add entries from the local blacklist file if it exists in $piholeDir directory
+# Remove empty lines and comments
+if [[ -f $blacklist ]] && [[ $tmpBlackList -ot $blacklist ]]; then
     echo "Getting the local blacklist from $piholeDir directory"
     awk -F'[# \t]' 'NF>0&&$1!="" {print $1}' $blacklist > $tmpBlackList
-    cat $tmpBlackList >> $tmpAdList
+else
+    if [[ -f $tmpBlackList ]]; then
+        echo "No need to update temporary blacklist."
+    else
+        echo -n "" > $tmpBlackList
+    fi
 fi
+cat $tmpBlackList >> $tmpAdList
 
-# Clean-up entries from the local whitelist file if it exists in $piholeDir directory
-echo -n "^$" > $tmpWhiteList
-if [[ -f $whitelist ]];then
+# If newer, clean-up entries from the local whitelist file if it exists in $piholeDir directory
+# Remove empty lines and comments
+if [[ -f $whitelist ]] && [[ $tmpWhiteList -ot $whitelist ]]; then
     echo "Getting the local whitelist from $piholeDir directory"
-    awk -F'[# \t]' 'NF>0&&$1!="" {print $1"$"}' $whitelist > $tmpWhiteList
+    awk -F'[# \t]' 'NF>0&&$1!="" {print $1"$"}' $whitelist > $tmpWhiteList 
+else
+    if [[ -f $tmpWhiteList ]]; then
+        echo "No need to update temporary whitelist."
+    else
+        echo -n "^$" > $tmpWhiteList
+    fi
 fi
 
 # Sort the aggregated results and remove any duplicates
 # Remove entries from the whitelist file if it exists in $piholeDir folder
+# Remove all subdomains if domain is already in list
 echo "Removing duplicates, whitelisting, and formatting the list of domains..."
-grep -vhE "^\s*(#|$)" $tmpAdList| 
-    sed $'s/\r$//'| 
-    awk -F. '{for (i=NF; i>1; --i) printf "%s.",$i;print $1}'| 
+awk -F. '{for (i=NF; i>1; --i) printf "%s.",$i;print $1}' $tmpAdList | 
     sort -t'.' -k1,2| uniq |  
     awk -F. 'NR!=1&&substr($0,1,length(p))==p {next} {p=$0".";for (i=NF; i>1; --i) printf "%s.",$i;print $1}'| 
     grep -vwf $tmpWhiteList |
     awk -v "IP=$piholeIP" '{sub(/\r$/,""); print "address=/"$0"/"IP}' > $tmpConf
+
+# Count how many entries from blacklist/whitelist were added so it can be displayed to the user
 numberOfSitesWhitelisted=$(cat $tmpWhiteList | wc -l | sed 's/^[ \t]*//')
 numberOfSitesBlacklisted=$(cat $tmpBlackList | wc -l | sed 's/^[ \t]*//')
 echo "$numberOfSitesWhitelisted domain(s) whitelisted, $numberOfSitesBlacklisted domain(s) blacklisted."
 
-# Count how many domains/whitelists were added so it can be displayed to the user
+# Count how many domains were added so it can be displayed to the user
 numberOfAdsBlocked=$(cat $tmpConf | wc -l | sed 's/^[ \t]*//')
 echo "$numberOfAdsBlocked ad domains blocked."
 
-# Turn the file into a dnsmasq config file
-sudo mv $tmpConf $eventHorizion
-
-# Restart DNS
-sudo service dnsmasq restart
+# Turn the file into a dnsmasq config file if necessary
+if cmp -s $tmpConf $eventHorizon
+then
+   echo "dnsmasq config file: $eventHorizon doesn't need to be updated"
+   rm $tmpConf
+else
+    echo "...updating configuration file and restarting dnsmasq"
+    sudo mv $tmpConf $eventHorizon
+    # Restart DNS
+    sudo service dnsmasq restart
+fi