diff --git a/jode/jode/GlobalOptions.java b/jode/jode/GlobalOptions.java
index 987f91f..4b50747 100644
--- a/jode/jode/GlobalOptions.java
+++ b/jode/jode/GlobalOptions.java
@@ -19,6 +19,7 @@
 
 package jode;
 import java.io.PrintStream;
+import java.util.StringTokenizer;
 
 public class GlobalOptions {
     public final static String version = "1.0";
@@ -30,13 +31,61 @@ public class GlobalOptions {
     public static int verboseLevel   = 0;
     public static int debuggingFlags = 0;
 
-    public static final int DEBUG_BYTECODE = 0x01;
-    public static final int DEBUG_VERIFIER = 0x02;
-    public static final int DEBUG_TYPES    = 0x04;
-    public static final int DEBUG_FLOW     = 0x08;
-    public static final int DEBUG_INOUT    = 0x10;
-    public static final int DEBUG_ANALYZE  = 0x20;
-    public static final int DEBUG_LVT      = 0x40;
+    public static final int DEBUG_BYTECODE = 0x001;
+    public static final int DEBUG_VERIFIER = 0x002;
+    public static final int DEBUG_TYPES    = 0x004;
+    public static final int DEBUG_FLOW     = 0x008;
+    public static final int DEBUG_INOUT    = 0x010;
+    public static final int DEBUG_ANALYZE  = 0x020;
+    public static final int DEBUG_LVT      = 0x040;
+    public static final int DEBUG_CHECK    = 0x080;
+    public static final int DEBUG_LOCALS   = 0x100;
+
+    public static final String[] debuggingNames = {
+	"bytecode", "verifier", "types", "flow", 
+	"inout", "analyze", "lvt", "check", "locals"
+    };
 
     public static boolean sanityChecks = false;
+
+    public static void usageDebugging() {
+	err.println("Debugging option: --debug=flag1,flag2,...");
+	err.println("possible flags:");
+	err.println("\tbytecode     " +
+		    "show bytecode, as it is read from class file.");
+	err.println("\tverifier     " +
+		    "show result of bytecode verification.");
+	err.println("\ttypes        " +
+		    "show type intersections");
+	err.println("\tflow         " +
+		    "show flow block merging.");
+	err.println("\tanalyze      " +
+		    "show analyzation order of flow blocks.");
+	err.println("\tinout        " +
+		    "show T1/T2 in/out set analysis.");
+	err.println("\tlvt          " +
+		    "dump LocalVariableTable.");
+	err.println("\tcheck        " +
+		    "do time consuming sanity checks.");
+	System.exit(0);
+    }
+
+    public static void setDebugging(String debuggingString) {
+	if (debuggingString.length() == 0 || debuggingString.equals("help"))
+	    usageDebugging();
+
+	StringTokenizer st = new StringTokenizer(debuggingString, ",");
+    next_token:
+	while (st.hasMoreTokens()) {
+	    String token = st.nextToken().intern();
+	    for (int i=0; i<debuggingNames.length; i++) {
+		if (token == debuggingNames[i]) {
+		    debuggingFlags |= 1 << i;
+		    continue next_token;
+		}
+	    }
+	    err.println("Illegal debugging flag: "+token);
+	    usageDebugging();
+	}
+    }
 }