How can I boot to command line by DEFAULT?

Are you asking about booting into single user mode? Look here

Boot argument options in OS X | MacFixIt - CNET Reviews

sudo nvram boot-args="-s"

This command will boot the system into Single User mode without needing to hold Command-S at startup.

qhil wrote:

Is there anyghing similar to the runlevels in Debian or so?

What are you trying to do? Booting into single user mode doesn't really have anything to do with runlevels. Plus, it would be running as root which is really not a good idea.

OS X does not have runlevels like Debian. Daemons and agents start up independently. They are not supposed to depend on any other services. It is a completely different philosophy and design than Linux.

If you just want a command-line login, you can always login as ">console" and that will give you a true user-level, command-line only interface.

In single user mode you are logged in as root which is not a good idea. The filesystem is read-only (until you change it to read/write) and some services will not be available. Single user mode should not be used as the default startup "level". By design the operating system starts the window server in multi user mode. You can kill the window server and run just the console with the following instructions.

From System Preferences > Accounts > Login Options

set the following options:

Automatic login: Off

Display login window as: Name and password

log out of your account. At the login window enter the following in the name field:

>console

Press the return key.

The window server will quit. Enter you user name then your password at the password: prompt.

Logging in as ">console" hasn't worked in years. The closest thing to what you want is to run Terminal in full-screen mode as a login item.

Linc Davis wrote:

Logging in as ">console" hasn't worked in years.

And which years might those be? Because it works in 10.8.5 in 2013 🙂

Not for me. It must be incompatible with FileVault.