--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -2507,7 +2507,8 @@ def unbundle(ui, repo, fname, **opts):
def update(ui, repo, node=None, clean=False, date=None):
"""update working directory
- Update the working directory to the specified revision.
+ Update the working directory to the specified revision, or the
+ tip of the current branch if none is specified.
If there are no outstanding changes in the working directory and
there is a linear relationship between the current version and the