diff --git a/yocto-poky/scripts/bitbake-prserv-tool b/yocto-poky/scripts/bitbake-prserv-tool
index 28c2416..fa31b52 100755
--- a/yocto-poky/scripts/bitbake-prserv-tool
+++ b/yocto-poky/scripts/bitbake-prserv-tool
@@ -86,6 +86,15 @@
 
 [ $# -eq 0 ] && help  && exit 1
 
+case $2 in
+*.conf|*.inc)
+    ;;
+*)
+    echo ERROR: $2 must end with .conf or .inc!
+    exit 1
+    ;;
+esac
+
 case $1 in
 export)
     do_export $2