fix typo


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@2378 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/README b/README
index 91b8711..32b21ec 100644
--- a/README
+++ b/README
@@ -85,7 +85,7 @@
   5. Do "make install", possibly as root if the destination permissions
      require that.
 
-  6. See if it works.  Try "valgrind --tool-memcheck ls -l".  Either
+  6. See if it works.  Try "valgrind --tool=memcheck ls -l".  Either
      this works, or it bombs out with some complaint.  In that case,
      please let us know (see valgrind.kde.org/bugs.html).