diff -r 34706a835d4a -r 8b4435aae40a mercurial/commands.py
--- a/mercurial/commands.py	Wed Sep 07 23:38:28 2005 -0700
+++ b/mercurial/commands.py	Wed Sep 07 23:57:59 2005 -0700
@@ -2003,5 +2003,12 @@
     except UnknownCommand, inst:
         u.warn("hg: unknown command '%s'\n" % inst.args[0])
         help_(u, 'shortlist')
+    except SystemExit:
+        # don't catch this is the catch-all below
+        raise
+    except:
+        u.warn("** unknown exception encountered, details follow\n")
+        u.warn("** report bug details to mercurial@selenic.com\n")
+        raise
 
     sys.exit(-1)