+usage = """%prog [options] [<location>]
+
+Pull the latest changes from the given URL or branch (defaulting to
+'origin'). This command works by popping all the patches from the
+stack, pulling the changes in the parent repository, setting the base
+of the stack to the latest parent HEAD and pusing the patches back
+(unless '--nopush' is specified). The 'push' operation can fail if
+there are conflicts. They need to be resolved and the patch pushed
+again.
+
+Note that this command doesn't perform any merge operation for the
+base of the stack, it only performs merges with the patches being
+pushed."""