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- So you have just learned

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about the Linux basic permissions.

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The thing about these
Linux basic permissions

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is that they were
introduced a long time ago.

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Now Linux is based on Unix

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and Unix is a very old operating system.

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It comes from the early 1970s

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and it means that the original idea

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of working with permissions
was a bit limited.

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And that is why we have had

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a couple of improvements to the system.

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And one of them is the
Advanced Permissions.

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So let's talk about the
Advanced Permissions.

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To start with, there is Set User ID,

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also referred to as SUID

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with an octal value of four.

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Set User ID on files means

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that you run the file as
the user owner of that file.

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And I will show you what that's all about

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in just a little bit.

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Set Group ID or SGID
with octal value of two.

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If you apply that on a file,

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then it means that you run the file

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as the group owner of that file.

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And if you run it on a directory

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then it sets the ownership

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on newly created items as the
group owner of that directory.

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In case you are wondering,

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hey, on Set User ID

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you didn't tell us what
it's doing on a directory.

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Why is that?

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Because it has no meaning on directories.

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Set Group ID has a meaning
on files and directories.

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Set User ID only has a meaning on files.

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And Sticky Bit only has
a meaning on directories.

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And the meaning is that Sticky Bit

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on directories allows
a user to delete files,

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if the user is file owner or
the user is directory owner.

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Now this needs a couple of demos.

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In the next video I will
demonstrate all of these.