improve hostname.sh changes

recipes-core/initscripts/files/hostname.sh

@@ -71,14 +71,9 @@ else
     hostname $(get_sn 37).$url
 fi
 
-#Add 127.0.0.0 entry to /etc/hosts if it is not already present
-grep "127.0.0.0" /etc/hosts > tmp/junk
-if [ -s /tmp/junk ]; then
-	rm /tmp/junk
-else
+if ! grep -q -i "127.0.0.0" /etc/hosts; then
         NAME=$(hostname)                                                        
         SHORTNAME=$(hostname | cut -b -16)                                      
         NEWLINE="127.0.0.0	$NAME	$SHORTNAME"                             
-        sed -e"/^127.0.0.1/a ${NEWLINE}" /etc/hosts > /tmp/hosts2   
-        mv /tmp/hosts2 /etc/hosts                                   
+        sed -i "/127.0.0.1/a ${NEWLINE}" /etc/hosts
 fi