document in manpage that port 0 is off.
issue
@@ -62,7 +62,7 @@ caches, so consult the README and memcached homepage for configuration
suggestions.
.TP
.B \-p, --port=<num>
-Listen on TCP port <num>, the default is port 11211.
+Listen on TCP port <num>, the default is port 11211. 0 means off.
.TP
.B \-U, --udp-port=<num>
Listen on UDP port <num>, the default is port 0, which is off.
