diff --git a/README.md b/README.md
index 8fe89fc..c581820 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,5 @@
 # Nasal Script Language
 
-[TOC]
-
 ## Introduction
 
 [Nasal](http://wiki.flightgear.org/Nasal_scripting_language) is a script language that used in [FlightGear](https://www.flightgear.org/).
@@ -56,7 +54,7 @@ Use these commands to get version of interpreter:
 
 > ./nasal -v | -version
 
-Use these commands to get version of interpreter:
+Use these commands to get help:
 
 > ./nasal -h | -help
 
diff --git a/main.cpp b/main.cpp
index 3d337d5..59b9b11 100644
--- a/main.cpp
+++ b/main.cpp
@@ -19,6 +19,7 @@ void help_interact()
 void help_cmd()
 {
 	std::cout
+	<<"nasal             | use interactive interpreter.\n"
 	<<"nasal -h -help    | get help.\n"
 	<<"nasal -v -version | get version of nasal interpreter.\n"
 	<<"nasal filename    | execute script file.\n";
@@ -153,7 +154,7 @@ int main(int argc,const char* argv[])
 	}
 	else if(argc==2 && (!strcmp(argv[1],"-h") || !strcmp(argv[1],"-help")))
 		help_cmd();
-	else if(argc==2)
+	else if(argc==2 && argv[1][0]!='-')
 	{
 		file=argv[1];
 		command="exec";
@@ -161,6 +162,10 @@ int main(int argc,const char* argv[])
 		return 0;
 	}
 	else
-		help_cmd();
+	{
+		std::cout
+		<<"invalid command.\n"
+		<<"use nasal -h to get help.\n";
+	}
     return 0;
 }
\ No newline at end of file
diff --git a/test/bf.nas b/test/bf.nas
index 8b1a4b4..e391f9e 100644
--- a/test/bf.nas
+++ b/test/bf.nas
@@ -151,8 +151,6 @@ var bf=func(program)
 {
     var paper=[];
     setsize(paper,131072);
-    #for(var i=0;i<131072;i+=1)
-    #    paper[i]=0;
     var ptr=0;
     var s=program;
     var len=size(s);
@@ -213,8 +211,8 @@ var bf=func(program)
                 return;
             }
             var label=pop(stack);
-            append(code,[jt,label]);
-            code[label][1]=size(code)-1;
+            append(code,[jt,label-1]);
+            code[label][1]=size(code)-2;
         }
     }
     if(size(stack))
@@ -227,25 +225,18 @@ var bf=func(program)
     for(var i=0;i<len;i+=1)
     {
         if(code[i][0]==add)
-        {
             paper[ptr]+=code[i][1];
-            if(paper[ptr]>255)
-                paper[ptr]-=256;
-            elsif(paper[ptr]<0)
-                paper[ptr]+=256;
-        }
         elsif(code[i][0]==mov)
             ptr+=code[i][1];
-        elsif(code[i][0]==in)
-            paper[ptr]=input()[0];
+        elsif(code[i][0]==jt and paper[ptr])
+            i=code[i][1];
+        elsif(code[i][0]==jf and !paper[ptr])
+            i=code[i][1];
         elsif(code[i][0]==out)
             print(chr(paper[ptr]));
-        elsif(code[i][0]==jt and paper[ptr])
-            i=code[i][1]-1;
-        elsif(code[i][0]==jf and !paper[ptr])
-            i=code[i][1]-1;
+        elsif(code[i][0]==in)
+            paper[ptr]=input()[0];
     }
-    print('\n');
     return;
 }