diff --git a/clamav.sh b/clamav.sh
index 0af138a..3d4b495 100644
--- a/clamav.sh
+++ b/clamav.sh
@@ -4,38 +4,44 @@
 #
 # !!! To receive best protection, you should setup a cronjob that executes this script every minute !!!
 #
+# This script requires the lockfile command provided by procmail
+#
 # Please set up the following variables to fit your system
 
 CLAMDIR="/var/lib/clamav"
 CLAMUSER="clamav"
 CLAMGROUP="clamav"
+LOCKFILE="/tmp/urlhaus.lock"
+TEMPDIR="/tmp/urlhaus/"
 
 # Don't change anything below this line
 
 RELOAD=0
 
-lockfile -r 0 /tmp/local.the.lock 2>/dev/null || exit 1
+lockfile -r 0 $LOCKFILE 2>/dev/null || exit 1
 
-rm -rf /tmp/urlhaus
-mkdir /tmp/urlhaus
+rm -rf $TEMPDIR
+mkdir $TEMPDIR
 
-curl -s https://urlhaus.abuse.ch/downloads/urlhaus.ndb -o /tmp/urlhaus/urlhaus.ndb
+curl -s https://urlhaus.abuse.ch/downloads/urlhaus.ndb -o $TEMPDIR/urlhaus.ndb
 
 if [ $? -eq 0 ]; then
-  clamscan --quiet -d /tmp/urlhaus /tmp/urlhaus 2>&1 >/dev/null
+  clamscan --quiet -d $TEMPDIR $TEMPDIR 2>&1 >/dev/null
   if [ $? -eq 0 ]; then
     if [ -f "$CLAMDIR"/urlhaus.ndb ]; then
-      MD5old=`md5sum "$CLAMDIR"/urlhaus.ndb`
-      MD5new=`md5sum /tmp/urlhaus/urlhaus.ndb`
-      if ! [ "$MD5old" = "$MD5new" ]; then
+      MD5old=$(md5sum "$CLAMDIR"/urlhaus.ndb | awk '{print $1}')
+      MD5new=$(md5sum $TEMPDIR/urlhaus.ndb | awk '{print $1}')
+      echo $MD5old
+      echo $MD5new
+      if [ "$MD5old" != "$MD5new" ]; then
         # Updated file
-        cp /tmp/urlhaus/urlhaus.ndb $CLAMDIR
+        cp $TEMPDIR/urlhaus.ndb $CLAMDIR
         chown $CLAMUSER.$CLAMGROUP "$CLAMDIR"/urlhaus.ndb
         RELOAD=1
       fi
     else
       # Looks like it's the first run
-      cp /tmp/urlhaus/urlhaus.ndb $CLAMDIR
+      cp $TEMPDIR/urlhaus.ndb $CLAMDIR
       chown $CLAMUSER.$CLAMGROUP "$CLAMDIR"/urlhaus.ndb
       RELOAD=1
     fi
@@ -46,5 +52,5 @@ if [ $RELOAD -eq 1 ]; then
   clamdscan --reload
 fi
 
-rm -rf /tmp/urlhaus
-rm -f /tmp/local.the.lock
+rm -rf $TEMPDIR
+rm -f $LOCKFILE