1 files changed, 17 insertions, 5 deletions

diff --git a/bin/NS2SetMac.sh b/bin/NS2SetMac.sh
index 51810ae..e6111c7 100755
--- a/bin/NS2SetMac.sh
+++ b/bin/NS2SetMac.sh
@@ -1,2 +1,6 @@
-# store/set MAC address for given interface
+# this script is part of networksettings2 package
+# purpose : set fixed MAC address for network devices that
+#           have random addresses (like usb)
+#
+
 NS2MacStore=/etc/NS2
@@ -6,3 +10,3 @@ NS2MacStore=/etc/NS2
 if [ -z "$1" ]
-then 
+then
   exit 0
@@ -10,6 +14,10 @@ fi
 
-if [ -f ${NS2MacStore}/$1.mac ] 
+if [ -f ${NS2MacStore}/$1.mac ]
 then
   # set this mac
-  /sbin/ifconfig $1 hw ether `cat ${NS2MacStore}/$1.mac`
+  X=`cat ${NS2MacStore}/$1.mac`
+  if [ ! -z "$X" ]
+  then
+    /sbin/ifconfig $1 hw ether $X
+  fi
 else
@@ -19,3 +27,7 @@ else
   X=${X%% *} # remove trailing spaces
-  echo ${X} > ${NS2MacStore}/$1.mac
+  if [ ! -z "$X" ]
+  then
+    # valid mac address
+    echo ${X} > ${NS2MacStore}/$1.mac
+  fi
 fi