Why do I appear 3 times “logged in” in macosx? (zsh and screen)

Question

I'm using the following options in order to launch a 'screen' session when I launch Terminal.app to my OSX Mountain Lion:

**~/.zshrc relevant option**
if [[ $STY = '' ]] then screen -UxR; fi # autoload screen

**~/.screenrc**
escape ^Bb
autodetach on
startup_message off # Turn off the splash screen
defscrollback 30000 # Use a 30000-line scrollback buffer

Then, when I launch the terminal and issue the 'who' command I see this:

➜  ~  who
atma     console  Aug  2 09:59 
atma     ttys000  Aug  2 11:32 
atma     ttys002  Aug  2 11:32 

The first line is the default 'ho-my-zsh' prompt.

I'm pretty sure there is a good explanation but out of curiosity why there are 2 tty's there and not 1? If I exit the screen, using the 'exit' command I get 1 console and 1 ttys:

Last login: Thu Aug  2 11:32:40 on ttys000
[screen is terminating]
➜  ~  who
atma     console  Aug  2 09:59 
atma     ttys000  Aug  2 11:32 

Shouldn't only 'console' be listed here?

Regards & thanks for your time!

Answer 1

The mac has you log in and it counts as being logged in on the console device at 09:59am; The terminal starts up a login shell for the current user (on ttys000 at 11:32am) and screen starts up a login shell for the current user within its virtual terminal (on ttys002 also at 11:32am). So this seems perfectly normal. That should explain why when you exit screen you're still seeing the console and ttys000 login as active. You might like this brief explanation of /dev/console/ and the console app.