The command that controls navigation tabs is view and the parameter is the name of the tab set followed the name of the tab to be selected:
In this case the tabset name is media the tab to select is picks. If you leave off the selected tab, the default is the first tab:
is the same as
For ultimate flexibility is it theoretically possible to switch out the top main navigation bar by specifying another tab set:
http://ccmixter.org/view/alt_tabs (this is a 404 because ccM doesn't have such a tab set name)
It's not considered good interface practice but we didn't want to restrict it just because it's a bad idea.
However you can create tabs sets that are used as 'subtabs' that you hook up in admin/tabs. When selecting the tab type you select subtab and enter the name of the subtab set. The URL is then extended to include the subtabs and the selected tab with there:
Command is "view", tab set is "media", selected tab in "media" is "extras" which invokes the subtab set called "ccmixter_extras", select tab within that is "stats" (which maps to a command "viewfile/stats" which displays the file mixter-files/pages/stats.php)
When you don't specify ANYTHING
Then the system will look at the 'Homepage' setting under Manage Site->Settings to figure out what to display. ccMixter has that set to view/media/home - again, command is view to bring up the media tab set and select the home tab
All this may bring up the question: "How come when I enter a command OTHER than view I still get a nav tab set?"
That's because the skin itself is (essentially) performing the view command on the default tab set. The view command exists so that there is an explicit way to say to the system: "Do the selected view tab and nothing else."