diff --git a/tools/update_revnum.py b/tools/update_revnum.py
index eafc1b9..fd37a90 100755
--- a/tools/update_revnum.py
+++ b/tools/update_revnum.py
@@ -3,11 +3,11 @@
 import os
 import re
 
-rev = os.popen('svnversion').read().strip()
+rev = os.popen('svnversion ..').read().strip()
 
 print "current rev is",rev
 assert ':' not in rev
 
 rfile = open('../IPython/Release.py').read()
 newcont = re.sub(r'revision\s*=.*', "revision = '%s'" % rev, rfile)
-open('../IPython/Release.py','w').write(newcont)
\ No newline at end of file
+open('../IPython/Release.py','w').write(newcont)