Hey everybody welcome to the next video of the Linux operating system module.
In this video we're gonna be going over run levels.
Now what are run levels run level.
Think of that as a mode that the that the operating system the Linux operating system is currently in.
Now when Linux starts up there is a default run love or default mode that is identified now a Linux
OS will be in some kind of mode or run level at all times as long as it's actually the opposite system
is actually running so the servers off it's not obviously not in a run mode so to check your current
run level it's who Dash are.
Now we're gonna hit a few of the the run levels but just understand that you can change the run levels
at different times depending on what role model you want to change it to.
You may have to restart the machine but we'll go over that in a second.
So run levels.
So level zero.
This tells the system to halt or shut down now.
So this is pretty common if you are not trying to restart you're just trying to shut it down completely
as soon as you hit the shutdown button.
Your OS goes into one level zero and then it starts shutting everything down.
Now Level 1 is single user mode does not support any network services Damon's and only route log ins
are allowed.
This is common for when you plug into the back of a server and you're trying to access a particular
system or your system.
Ne is having some sorta sort of issues you can you can load into run level 1 to be able to handle a
lot of this.
So think of the equivalent of this is to like safe mode in Windows if you if you're familiar with that
it doesn't start adding network services just it just allows the users to log in or the admin to log
in run level to this is multi-user mode exactly the same as run level one but you can use non root Loggins.
So if you have a standard account you can log in as well but keep in mind there's still no networking
or anything like that.
Now run Level 3 is a multi-user Mode with Networking and all the demons that normally come with it.
This is common for Linux that have no gooey or headlight or that have been installed and a headless
mode.
So you're going to see run Level 3 on a server as an example run low for this is undefined because it
gives you a spot for the user to define exactly how they want to start.
So if you have a custom way you want to you want to run the OS.
You can put it here and it's a spot for it now run Level 5.
This is where the gooey is started up or grab the grub load or whatever you want to use it's it's it's
loading up the the gooey the system operate the networking services the any of the demons that you have
set up so it's the standard equivalent to run Level 3 now run Level 5 is currently what your ubuntu
server is in because it's not just running and it's not running headless mode.
You have the gooey available you have multi-user support and you have all of the services running so
that would land you and run the five.
Now when you hit the reboot button your machine goes into run Level Six get familiar with the run levels
this is more of a good to know type thing.
Good to know.
To identify what run level the machine is.
So for example if you're on an engagement you're trying to log in as another user and it's not allowing
YouTube knowing what the run level was may help you on that particular case.