diff --git a/tools/python/xen/xm/main.py b/tools/python/xen/xm/main.py
index 1fb4cc2061..5239ae4156 100644
--- a/tools/python/xen/xm/main.py
+++ b/tools/python/xen/xm/main.py
@@ -291,6 +291,11 @@ all_commands = (domain_commands + host_commands + scheduler_commands +
 def cmdHelp(cmd):
     """Print help for a specific subcommand."""
     
+    for fc in SUBCOMMAND_HELP.keys():
+        if fc[:len(cmd)] == cmd:
+            cmd = fc
+            break
+    
     try:
         args, desc = SUBCOMMAND_HELP[cmd]
     except KeyError: