updated syntax, thanks to Chris Handy for spotting it

doc/sphinx/tutorial/increasing_your_hitrate.rst

@@ -32,8 +32,8 @@ Tool: varnishlog
 
 When you have identified the an URL which is frequently sent to the
 backend you can use varnishlog to have a look at the whole request.
-``varnishlog -c -o /foo/bar`` will give the whole (-o) requests coming
-from the client (-c) matching /foo/bar. 
+``varnishlog -c -m 'RxURL:^/foo/bar`` will give the whole (-o)
+requests coming from the client (-c) matching /foo/bar.
 
 For extended diagnostics headers, see
 http://www.varnish-cache.org/trac/wiki/VCLExampleHitMissHeader