diff --git a/bin/obj2gltf.js b/bin/obj2gltf.js
index 5008a3d..82fc4e1 100644
--- a/bin/obj2gltf.js
+++ b/bin/obj2gltf.js
@@ -23,14 +23,24 @@ var argv = yargs
             alias : 'i',
             describe : 'Path to the obj file.',
             type : 'string',
-            normalize : true,
-            demandOption : true
+            demandOption : true,
+            coerce : function (p) {
+                if (p.length === 0) {
+                    throw new Error('Input path must be a file name');
+                }
+                return path.resolve(p);
+            }
         },
         output : {
             alias : 'o',
             describe : 'Path of the converted glTF or glb file.',
             type : 'string',
-            normalize : true
+            coerce : function (p) {
+                if (p.length === 0) {
+                    throw new Error('Output path must be a file name');
+                }
+                return path.resolve(p);
+            }
         },
         binary : {
             alias : 'b',