diff --git a/heartbeat/findif.sh b/heartbeat/findif.sh
index fec2ff349..495a71c89 100644
--- a/heartbeat/findif.sh
+++ b/heartbeat/findif.sh
@@ -1,163 +1,163 @@
 #!/bin/sh
 ipcheck_ipv4() {
   local ip=$1
   echo "$ip" | grep -qs '^[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}$'
   if [ $? -ne 0 ] ; then
     return 1
   fi
   echo "$ip" | awk -F. '{if(NF!=4)exit(1);for(i=1;i<=4;i++)if(!($i>=0&&$i<=255))exit(1)}'
 }
 ipcheck_ipv6() {
   local ipaddr=$1
   echo "$ipaddr" | grep -qs "[^0-9:a-fA-F]"
   if [ $? = 1 ] ; then
     return 0
   else
     return 1
   fi
 }
 ifcheck_ipv4() {
   local ifcheck=$1
   local ifstr
   local counter=0
   local procfile="/proc/net/dev"
   while read LINE
   do
     if [ $counter -ge 2 ] ; then
       ifstr=`echo $LINE | cut -d ':' -f 1`
       if [ "$ifstr" = "$ifcheck" ] ; then
         return 0
       fi
     fi
     counter=`expr $counter + 1`
   done < $procfile
   return 1
 }
 ifcheck_ipv6() {
   local ifcheck="$1"
   local ifstr
   local procfile="/proc/net/if_inet6"
   while read LINE
   do
     ifstr=`echo $LINE | awk -F ' ' '{print $6}'`
     if [ "$ifstr" = "$ifcheck" ] ; then
       return 0
     fi
   done < $procfile
   return 1
 }
 prefixcheck() {
   local prefix=$1
   local prefix_length=${#prefix}
   local prefix_check=$2
 
   if [ $prefix_length -gt 3 -o $prefix_length -eq 0 ] ; then
     return 1
   fi
-  echo "$prefix" | grep "[^0-9]"
+  echo "$prefix" | grep -qs "[^0-9]"
   if [ $? = 0 ] ; then
     return 1
   fi
   if [ $prefix -lt 1 -o $prefix -gt $prefix_check ] ; then
     return 1
   fi
   return 0
 }
 getnetworkinfo()
 {
   ip -o -f inet route list match $OCF_RESKEY_ip table local scope host | (while read LINE;
   do
     IP=`echo $LINE | awk '{print $2}'`
     case $IP in
     */*)
       set -- $LINE
       break
       ;;
     esac
   done
   echo $LINE)
 }
 
 findif()
 {
   local match="$OCF_RESKEY_ip"
   local family="inet"
   local scope
   local NIC="$OCF_RESKEY_nic"
   local NETMASK="$OCF_RESKEY_cidr_netmask"
   local BRDCAST="$OCF_RESKEY_broadcast"
   echo $match | grep -qs ":"
   if [ $? = 0 ] ; then
-    `ipcheck_ipv6 $match`
+    ipcheck_ipv6 $match
     [ $? = 1 ] && return 6
     if [ -n "$NIC" ] ; then
-      `ifcheck_ipv6 $NIC`
+      ifcheck_ipv6 $NIC
       [ $? = 1 ] && return 6
     else
       echo $match | grep -qis '^fe80::'
       if [ $? = 0 ] ; then
         return 1
       fi
     fi
     if [ -n "$NETMASK" ] ; then
-      `prefixcheck $NETMASK 128`
+      prefixcheck $NETMASK 128
       [ $? = 1 ] && return 6
       match=$match/$NETMASK
     fi
     family="inet6"
   else
-    `ipcheck_ipv4 $match`
+    ipcheck_ipv4 $match
     [ $? = 1 ] && return 6
     if [ -n "$NIC" ] ; then
-      `ifcheck_ipv4 $NIC`
+      ifcheck_ipv4 $NIC
       [ $? = 1 ] && return 6
     fi
     if [ -n "$NETMASK" ] ; then
-      `prefixcheck $NETMASK 32`
+      prefixcheck $NETMASK 32
       [ $? = 1 ] && return 6
       match=$match/$NETMASK
     fi
     if [ -n "$BRDCAST" ] ; then
-      `ipcheck_ipv4 $BRDCAST`
+      ipcheck_ipv4 $BRDCAST
       [ $? = 1 ] && return 6
     fi
     scope="scope link"
   fi
   if [ -n "$NIC" ] ; then
     # NIC supports more than two.
     set -- `ip -o -f $family route list match $match $scope | grep "dev $NIC"`
   else
     set -- `ip -o -f $family route list match $match $scope`
   fi
   if [ $# = 0 ] ; then
     case $OCF_RESKEY_ip in
     127.*)
       set -- `getnetworkinfo`
       shift;;
     esac
   fi
   if [ -z "$NIC" -o -z "$NETMASK" ] ; then
     [ $# = 0 ] && return 1
     case $1 in
     */*) : OK ;;
     *)
       return 1 ;;
     esac
   fi
   [ -z "$NIC" ] && NIC=$3
   [ -z "$NETMASK" ] && NETMASK=${1#*/}
   if [ $family = "inet" ] ; then
     if [ -z "$BRDCAST" ] ; then
       if [ -n "$7" ] ; then
         set -- `ip -o -f $family addr show | grep $7`
         [ "$5" = brd ] && BRDCAST=$6
       fi
     fi
   else
-    if [ -z "$OCF_RESKEY_nic" -a "$NETMASK" -ne "${1#*/}" ] ; then
+    if [ -z "$OCF_RESKEY_nic" -a "$NETMASK" != "${1#*/}" ] ; then
       return 1
     fi
   fi
   echo "$NIC netmask $NETMASK broadcast $BRDCAST"
   return 0
 }