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In this video we're going to cover some of the main Linux operating system components in the Microsoft

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section.

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We talked about Windows processes Linux operating systems also run processes.

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They work a little bit differently.

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Linux processes are classified as either parent or child.

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Processes like you would probably guess child processes are processes that are created from parent processes.

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When a parent process creates a child process it is called a fork each process is assigned a unique

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idea the ion I.T. process has process idea of one because it is the only process that does not have

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a parent process and is at the top of the process tree to view processes in the terminal you can run

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the P.S. command and then to see a list of available options for different data that can be provided

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from that command you can run dash dash help and then all and then it gives you an explanation of the

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miscellaneous options that you can add to that command by throw up here can see some more of the options

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that are available.

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I like to add the A E and F options so I'll go ahead and do that by entering.

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P.S. dash each miscellaneous option that I like to use.

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So a and then here's a nice list of the processes running on my Linux operating system.

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When I go to the top here here you can see the process I.D. and then parent process idea.

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And then you see the relationship between processes I run.

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P.S. tree

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and this is really cool because it gives you a nice visual representation of how everything's tied together

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between the processes

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operating systems can be used by multiple users at the same time to decide between who can access what

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file permissions are used to control access to system files to maintain a secure system these permissions

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must be as strict as possible to prevent malicious users from accessing resources to see what permissions

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a file has in Linux you can enter the terminal command.

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I'll ask Alec to add the dash l command the values in the left column represent the permissions for

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each file

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to modify file permissions you can use the C H M O D command.

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So in this example I assign the permission values 7 7 7 to the file named file and as you can see the

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highest permission that you can assign to a file is 7 4 stands for read 2 stands for right and then

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1 stands for.

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Execute

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so using C HMO D 7 7 7 and the file name you would provide full access to that file 1 really valuable

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command and Linux is pseudo which stands for super user.

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Do some commands will not execute without super user rights.

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If a command needs to be used but the current user does not have permissions to the file.

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The pseudo command can be used on demand to give a user super user rights when the pseudo command is

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entered.

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The user will be prompted to enter a user password that must be entered before the user rights are elevated.

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It is very common to encounter the pseudo log in requirement when you are using Linux terminal commands.

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Some links is short for symbolic links so instead of entering a long path for a file or directory you

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can use a sim link as a shortcut to access the file or directory

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OK.

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So here I am in my Linux lab machine.

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I'm going to create a directory with a really long folder path and then I'll show you how to create

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assembly so I can access the same directory.

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Both our entering a really long path.

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So first I'm going to enter the command M.K..

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Are and I'm going to make a new directory called backups and then to navigate to that directory I'm

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going to use the command D which stands for change directory which is another very commonly used Linux

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command to change directory and if I just hit tab then I can see some of the directories that I can

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jump to based on where I am in my Linux terminal and then I can either type in backups and hit forward

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slash and enter.

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That takes me right to my backups directory or I'll go back to the beginning with just entering S.D.

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again or I can just do CDMA.

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And then part of the name of the directory and then I can I can tab it out and if I had folders within

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this backups directory I could just keep hitting tab to navigate through that so I'm going to enter

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my backups directory and then I'm going to make another directory within their called Monday and off

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CDE and tab.

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You can see I can navigate to my Monday folder just to make this example match the PowerPoint slide.

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I'll go ahead and create new directories to match each weekday

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okay.

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So now we have our Friday directory

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and you can see that if I wanted to navigate to that directory even though I can tab it out have to

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remember this long path to get there.

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So now we'll create a assembling to access the Friday directory by using a shortcut word that we define

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with within the assembling configuration.

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So before I create the assembly I'm going to add a file to this directory so that we least have something

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to to list when we access it the touch command will create a file.

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So I'll say touch and then the file name will be file that T T.

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Now when I do I was minus Al in this directory.

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I have a file to reference here so we go all way back to the beginning and to make a assembling we'll

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use the command line space dash as the path of the original directory that we want to create assembling

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for say backups and I'll just have it all the way out.

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And then the name of our symbol Inc or shortcut and I'll call it Friday.

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I can spell Friday link

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so now to access our assembling.

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I can simply just navigate to it just like I would any other directory so I'll say change directory

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to Friday link to al us minus Al to list the contents of that directory.

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There you can see I have my file.

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So I was able to jump directly to this directory or folder if that shortcut simile.

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The last Linux topic I want to cover is demons.

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These are programs that run as background processes and they are equivalent to services that run Windows

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operating system one unique thing you should know about demons is since their system processes their

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parent process is normally going to be the process which has a process I.D. of one

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some common demon examples would be things like DCP RTP and SS age and you'll notice that their names

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typically end with a D.

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As you see here.