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If you have already created a file or directory and needed to change the security settings on it.

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If you have different utilities for this purpose are available in Linux, the section and this whole

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lecture, you will learn how to change the existing permission, the default owner and the default group

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settings for a file or directory.

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So my name is Stephan, the complainant or lecturer of our course.

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Let's get started.

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The mode command allows you to change the security settings for files and directories, the command

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mode here.

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So the command format is like this.

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So firstly you're going to enter the mode.

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Then options came here.

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Actually, let's hope, let's use the marker here.

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So firstly you need to enter the c h mode.

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And after that after mode, you will operate the options.

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Options.

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And after that you will enter the mode.

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And after lastly is file that you want to change the comments and permissions on it.

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So in order to do that.

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The mode parameter here actually.

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Oops.

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Yeah.

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The mode parameter allows you to set the security settings for either octal or symbolic mode.

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So the octal mode settings are pretty straightforward.

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So just use the standard three digit octal code that you learned in previous lecture.

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Remember this here?

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Yeah.

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Remember this.

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This is the permissions and your descriptions in binary and octal.

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So if you want to make something like let's create a new file, you know, and torch my new file, we

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already have my new file.

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Or let's actually my ultra new file.

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Yeah, my ultra new file.

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And here, let's actually la my ultra new file.

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And as you can see, this is following permissions right now.

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Right.

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Actually, let's open a new here and copy this and make examples from it here as so as you can see,

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here we have.

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This.

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This is just.

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We will ignore it at, uh, you will you learn actually this in previous lectures that this is a file

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types.

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So in this case it's just a regular file.

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So we will ignore it and we will copy this.

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We will ignore it.

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First character.

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Copy this.

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Actually, let's go.

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Here.

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So now.

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That's it.

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Now I will show you right here.

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So, as you can see here.

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RW is.

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RW is 110 then.

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Here are minus minus our null null here 101 hundred again.

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So after that, in octal, actually we are seeing the six.

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Zero zero.

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So that the permission for this file is my ultra file.

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Is this right?

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In octal and here in permission.

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Here.

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So.

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As I said, the mode parameter allows you to set the security settings using either octal or symbolic

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mode.

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So in order to change this here, for example, mode six, let's actually use 760.

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And here let's see what this 160 is.

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So seven is rw x, then it comes six RW And after that zero is 000 and that's it.

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And so let's see, what is this in?

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A binary.

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So 111 rw is 110 and 000.

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Right.

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Yeah.

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Here.

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And after that it is.

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760.

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And this is going to be my ultra file, the new my ultra file permission and this new permission.

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Here.

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Now let's use this mode.

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Then your permission and then file or directory name.

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In this case, my ultra new file.

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And here, let's run it again.

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And that's it.

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As you can see here, we got the desired result here.

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So let's see.

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Let's compare these results here.

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As you can see here, these are exactly the same result.

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So this table will help you in order to use that.

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So the Oakdale file permissions are automatically applied, applied to the file indicator.

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So the symbolic mode permissions are not so easy to implement.

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So instead of using the normal string of three sets of three characters, the Mod command takes a different

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approach.

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So.

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In order to do that.

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Here.

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So in this mode, firstly you're going to enter mode and then ugoa here.

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Yeah, this doesn't make sense, but you will understand here.

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So ugoa here.

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And after that plus minus or equal, you will enter one of this characters and after that you have this

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rw x uppercase to go.

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So you will enter one of those here.

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This doesn't make perfectly good sense, right?

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So the first group of characters defines to whom the new permissions to apply.

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That's actually UJO are not like that.

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S t ug o.

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And here we're going to have the Hugo.

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All right.

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Who user group or here and so on.

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You will have different groups here.

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So.

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The first group of characters defines to whom the new permission to apply.

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In this case, you is.

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Yeah, in this case, actually.

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Actually.

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Sorry for this.

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So let's copy this so you can see better here.

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So in this case the you.

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For user, the G for group and O for others or everyone else.

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And R for all of this group is here.

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So this will assign to R So the next symbol is used to indicate whether you want to add the permission

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to the existing permission with plus subtract the permission from the existing permission from minus

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or set the permission to the value.

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Finally, the third symbol is the permission used for setting.

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So you may notice that there are more than the normal r w x values here.

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So the additional settings are here.

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So actually let me write that down here.

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So here the S is for set.

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S is for set s uid or SG ID on execution.

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And here we are.

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T is for setting sticky bit set sticky bit which I will explain all of this here u is to set set permissions

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to the owners owners permission.

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The G here.

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The G is to set the permissions.

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Set.

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Permissions.

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Oops.

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Permissions to the groups.

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Groups, Permission.

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And.

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Your.

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And lastly, all here is used for to set permissions to others permission.

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So.

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Here.

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The use for permissions would like this so see mode.

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Or.

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Plus are my ultra new file.

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And let's actually try it again.

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And here, as you can see here, we got different results from here.

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So.

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It's actually.

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See what happens.

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And this is the actually here, the test one, test two.

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And this is test three here.

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So.

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RW Actually, it's not permission.

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Yeah.

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One, two, three, and that's it.

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So here, as you remember, RW X is 111110 and 100110 and 100.

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And here we will have for this 111100.

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So seven.

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And actually it's the first is seven and then it comes to six.

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And lastly.

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100 is four and not here for sorry for this.

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This is, uh, six.

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Four for and seven six and lastly for seven.

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Six for.

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So the here as you remember here, the O plus R entry also read permission to whatever permission that

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everyone security level already had.

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So the U minus X and removes the execute permissions that the user already had.

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So in order to do that let's actually do this.

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C'mon.

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C h mode u minus x, And here after that we will use the my ultra new file and a my my ultra new file.

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And as you can see here, we just change that.

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Let's try that now.

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So this one was our my.

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My ultra new my ultra file.

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They are they made it wrong here.

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Test three actually my ultra new file.

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New file.

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And lastly, new file.

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And here we will have this.

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Let's load it first.

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And here.

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One, two, three.

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And actually, the second parameters are same, but the first we changed with took the execute permissions

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from it.

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Let's actually try it now.

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Our W was 110.

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And again our W was 110.

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And lastly our was 1100, which is.

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Six, six, four.

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And this was our my actually.

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Let's test it again.

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110.

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Six.

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Six?

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Six.

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Six four.

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Yeah, that's true.

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Ultra new file.

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Ultra new file.

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And this is test four.

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And that's it with our lecture.

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I hope and I will also share these files with you.

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So I'm waiting you in next lecture.