In this video we're going to cover some of the main Linux operating system components in the Microsoft
section.
We talked about Windows processes Linux operating systems also run processes.
They work a little bit differently.
Linux processes are classified as either parent or child.
Processes like you would probably guess child processes are processes that are created from parent processes.
When a parent process creates a child process it is called a fork each process is assigned a unique
idea the ion I.T. process has process idea of one because it is the only process that does not have
a parent process and is at the top of the process tree to view processes in the terminal you can run
the P.S. command and then to see a list of available options for different data that can be provided
from that command you can run dash dash help and then all and then it gives you an explanation of the
miscellaneous options that you can add to that command by throw up here can see some more of the options
that are available.
I like to add the A E and F options so I'll go ahead and do that by entering.
P.S. dash each miscellaneous option that I like to use.
So a and then here's a nice list of the processes running on my Linux operating system.
When I go to the top here here you can see the process I.D. and then parent process idea.
And then you see the relationship between processes I run.
P.S. tree
and this is really cool because it gives you a nice visual representation of how everything's tied together
between the processes
operating systems can be used by multiple users at the same time to decide between who can access what
file permissions are used to control access to system files to maintain a secure system these permissions
must be as strict as possible to prevent malicious users from accessing resources to see what permissions
a file has in Linux you can enter the terminal command.
I'll ask Alec to add the dash l command the values in the left column represent the permissions for
each file
to modify file permissions you can use the C H M O D command.
So in this example I assign the permission values 7 7 7 to the file named file and as you can see the
highest permission that you can assign to a file is 7 4 stands for read 2 stands for right and then
1 stands for.
Execute
so using C HMO D 7 7 7 and the file name you would provide full access to that file 1 really valuable
command and Linux is pseudo which stands for super user.
Do some commands will not execute without super user rights.
If a command needs to be used but the current user does not have permissions to the file.
The pseudo command can be used on demand to give a user super user rights when the pseudo command is
entered.
The user will be prompted to enter a user password that must be entered before the user rights are elevated.
It is very common to encounter the pseudo log in requirement when you are using Linux terminal commands.
Some links is short for symbolic links so instead of entering a long path for a file or directory you
can use a sim link as a shortcut to access the file or directory
OK.
So here I am in my Linux lab machine.
I'm going to create a directory with a really long folder path and then I'll show you how to create
assembly so I can access the same directory.
Both our entering a really long path.
So first I'm going to enter the command M.K..
Are and I'm going to make a new directory called backups and then to navigate to that directory I'm
going to use the command D which stands for change directory which is another very commonly used Linux
command to change directory and if I just hit tab then I can see some of the directories that I can
jump to based on where I am in my Linux terminal and then I can either type in backups and hit forward
slash and enter.
That takes me right to my backups directory or I'll go back to the beginning with just entering S.D.
again or I can just do CDMA.
And then part of the name of the directory and then I can I can tab it out and if I had folders within
this backups directory I could just keep hitting tab to navigate through that so I'm going to enter
my backups directory and then I'm going to make another directory within their called Monday and off
CDE and tab.
You can see I can navigate to my Monday folder just to make this example match the PowerPoint slide.
I'll go ahead and create new directories to match each weekday
okay.
So now we have our Friday directory
and you can see that if I wanted to navigate to that directory even though I can tab it out have to
remember this long path to get there.
So now we'll create a assembling to access the Friday directory by using a shortcut word that we define
with within the assembling configuration.
So before I create the assembly I'm going to add a file to this directory so that we least have something
to to list when we access it the touch command will create a file.
So I'll say touch and then the file name will be file that T T.
Now when I do I was minus Al in this directory.
I have a file to reference here so we go all way back to the beginning and to make a assembling we'll
use the command line space dash as the path of the original directory that we want to create assembling
for say backups and I'll just have it all the way out.
And then the name of our symbol Inc or shortcut and I'll call it Friday.
I can spell Friday link
so now to access our assembling.
I can simply just navigate to it just like I would any other directory so I'll say change directory
to Friday link to al us minus Al to list the contents of that directory.
There you can see I have my file.
So I was able to jump directly to this directory or folder if that shortcut simile.
The last Linux topic I want to cover is demons.
These are programs that run as background processes and they are equivalent to services that run Windows
operating system one unique thing you should know about demons is since their system processes their
parent process is normally going to be the process which has a process I.D. of one
some common demon examples would be things like DCP RTP and SS age and you'll notice that their names
typically end with a D.
As you see here.