--- linux.sh.orig	2014-04-25 18:48:24.061563150 +1000
+++ linux.sh	2014-04-25 21:05:34.088637714 +1000
@@ -164,10 +164,12 @@
     ExecNoCheck $ifconfig $TSP_HOME_INTERFACE inet6 del $TSP_PREFIX::1/64
 
     subif="`SubInterfaces`"
-    echo "$subif" | while read sub int ; do
-       PREF="`SubNet "${TSP_PREFIX}::0/${TSP_PREFIXLEN}" "$sub"`"
-       ExecNoCheck $ifconfig "$int" inet6 del ${PREF}::1/64
-    done
+    if [ ! -z "$subif" ]; then
+       echo "$subif" | while read sub int ; do
+          PREF="`SubNet "${TSP_PREFIX}::0/${TSP_PREFIXLEN}" "$sub"`"
+          ExecNoCheck $ifconfig "$int" inet6 del ${PREF}::1/64
+       done
+    fi
   fi
 
   # Delete default IPv6 route(s).
@@ -276,17 +278,19 @@
    Exec $ifconfig $TSP_HOME_INTERFACE add $TSP_PREFIX::1/64
 
    subif="`SubInterfaces`"
-   echo "$subif" | while read sub int ; do
-      PREF=`echo $TSP_PREFIX | sed 's/00$//'`
-      OLDADDR=`$ifconfig "$int" | grep "inet6.* $PREF" | sed -e "s/^.*inet6 addr: //" -e "s/ Scope.*\$//"`
-      if [ ! -z $OLDADDR ]; then
-         Display 1 "Removing old IPv6 address $OLDADDR from $int"
-         Exec $ifconfig "$int" inet6 del $OLDADDR
-      fi
-      PREF="`SubNet "${TSP_PREFIX}::0/${TSP_PREFIXLEN}" "$sub"`"
-      Display 1 "Adding prefix ${PREF} to $int"
-      Exec $ifconfig "$int" inet6 add "${PREF}::1/64"
-   done
+   if [ ! -z "$subif" ]; then
+      echo "$subif" | while read sub int ; do
+         PREF=`echo $TSP_PREFIX | sed 's/00$//'`
+         OLDADDR=`$ifconfig "$int" | grep "inet6.* $PREF" | sed -e "s/^.*inet6 addr: //" -e "s/ Scope.*\$//"`
+         if [ ! -z $OLDADDR ]; then
+            Display 1 "Removing old IPv6 address $OLDADDR from $int"
+            Exec $ifconfig "$int" inet6 del $OLDADDR
+         fi
+         PREF="`SubNet "${TSP_PREFIX}::0/${TSP_PREFIXLEN}" "$sub"`"
+         Display 1 "Adding prefix ${PREF} to $int"
+         Exec $ifconfig "$int" inet6 add "${PREF}::1/64"
+      done
+   fi
 
    # Stop radvd daemon if it was running. Twice.
    /etc/init.d/radvd stop
@@ -309,9 +313,10 @@
 };
 EOF
 
-   echo "$subif" | while read sub int ; do
-      PREF="`SubNet "${TSP_PREFIX}::0/${TSP_PREFIXLEN}" "$sub"`"
-      cat >> "$rtadvdconfigfile" <<EOF
+   if [ ! -z "$subif" ]; then
+      echo "$subif" | while read sub int ; do
+         PREF="`SubNet "${TSP_PREFIX}::0/${TSP_PREFIXLEN}" "$sub"`"
+         cat >> "$rtadvdconfigfile" <<EOF
 interface $int
 {
   AdvSendAdvert on;
@@ -323,7 +328,8 @@
   };
 };
 EOF
-   done
+      done
+   fi
 
    # Start the radvd daemon.
    Display 1 "Starting radvd: $rtadvd -u radvd -C $rtadvdconfigfile"