--- a/mercurial/commands.py	Sat Oct 18 16:09:07 2008 +0200
+++ b/mercurial/commands.py	Sat Oct 18 16:50:03 2008 +0200
@@ -1335,6 +1335,19 @@
             else:
                 ui.write(' %-*s   %s\n' % (m, f, h[f]))
 
+        exts = list(extensions.extensions())
+        if exts:
+            ui.write(_('\nenabled extensions:\n\n'))
+            maxlength = 0
+            exthelps = []
+            for ename, ext in exts:
+                doc = (ext.__doc__ or _('(no help text available)'))
+                ename = ename.split('.')[-1]
+                maxlength = max(len(ename), maxlength)
+                exthelps.append((ename, doc.splitlines(0)[0].strip()))
+            for ename, text in exthelps:
+                ui.write(_(' %s   %s\n') % (ename.ljust(maxlength), text))
+
         if not ui.quiet:
             addglobalopts(True)