need help with a question?
 

what is the command to switch desktops?

If you mean switching between virtual desktop/workspace, it depends on the desktop environment you use. In Gnome, it is "Ctrl + Alt + left/right arrow key". I don't know if there are other faster ways, though.

You need to tell people what system you are using...and it would be really helpful if you phrase your subject in a meaningful manner. Say "switching between desktops" which would help you get quicker answers and helps other people with same problem zero in on your post.

Tux,

my guess would be he's using slack and trying to start something other than kde from the consol login.