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Now that you know a little bit about
these targets, let's explore how to work with them.

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Here on the slide.
You see the commands.

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Let
me demonstrate.

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So, systemctl get default
showing the default target.

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I want to change
that and I'm going to

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use sudo systemctl set
default on multi user target.

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For now, nothing is changing. But this is the default target and
it means that if I'm going to reboot, we should see the change.

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Let me reboot here.
I'm in multi user target,

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no graphical user interface
and I can log in.

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Let me
do that.

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And now systemctl list dependencies is showing what? Well,
it's showing everything that is happening in the multi user

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target. And there you can see that the multi
user target is taking care of all these service units.

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And then by itself it includes a basic
target and even more if you scroll down further.

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Now I would like to show
you how to switch to a different

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target and I'm using sudo systemctl
isolate on emergency target to do so.

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Systemctl isolate is what you will
use if you want to get

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from a target that has more
to a target that has less.

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And oh boy, what do we get? Now
it's telling us I'm in emergency mode. And

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what is it telling? It's saying cannot
open access to console, root account is locked.

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And what happens if I press enter? Well, if I
press enter then sadly I can't get into the emergency mode.

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Emergency target requires access
to the root account.

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I better get back to my
normal target and enter in there.

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Then I can use sudo passwd on root because if
I don't have a root password, I don't get in.

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I'll later show you how you can hack
the root password if that is required, but for

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now I'm just setting it manually and let
me use this systemctl isolate on emergency target again.

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So this is what you get in the emergency
target. And the problem in the emergency target is you

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need to enter the root password. Well, now we
have a root password, so let me enter it and

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let me use systemctl list units for an
overview of all the units that are currently loaded.

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Now this is emergency target.
It's a special rescue environment

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and that only loads
a minimal amount of units.

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Now I'm okay with the emergency target
and that means that I want to get

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back to my normal operational state and
I'm going to use systemctl start default target.

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The default target. Well, that was multi user target,
right? I don't want to go to multi user target.

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I'm going to use systemctl start graphical target and
that is bringing me back to the full graphical environment.