Troubleshoot File and Directory Permissions
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Video Transcription
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>> Hey there Cybrarians,
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welcome back to the Linux plus course here at Cybrary.
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I'm your instructor Rob Goelz and in today's lesson,
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we're going to be talking about file
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and directory permission issues.
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Upon completion of today's lesson,
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you're going to be able to understand the types
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of file and directory permissions issues that
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a user is going to be likely
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to encounter and we're going to see
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tools that we can use to
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troubleshoot and resolve these types of issues.
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Users often run into
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file permission issues any time that
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they trying to open or modify a file.
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To troubleshoot file permission issues,
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we can view permissions
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using our old friend the list command.
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We can use ls-al.
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Now that's going to display
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the user and group ownership of the file,
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and we can check the UGO and RWX
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permissions on the file as well by using ls-al.
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Next, we might want to check
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the user group membership using the id command,
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and if a user needs to be added
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to the group that they're not in,
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we can add the user using usermod.
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If a user is not an owner of a file but should be,
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we can make them the owner,
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and we can use the chown command,
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change owner, chown command.
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Now, users can hit directory permission issues
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as well as file issues when they're trying to read,
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write, copy or access files in a directory.
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The steps to troubleshoot file permissions are
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the same for directory permissions for the most part,
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but we can run ls-ld and
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that will give us the permissions on the directory.
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Now, once we've done that,
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we're going to want to do the same thing.
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We're going to want to check user and
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group ownership of the directory and we're going
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to want to check UGO/RWX permissions
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on the directory as well.
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But keep in mind the RWX permissions for
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the directory are a little bit
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different than what we saw for files.
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Example, the R permission
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is to view the directories files.
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Read or view the files.
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But the write command is to create,
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move, modify, and remove files in a directory.
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It's not just writing, it's doing a lot of things.
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Then the execute or x permission is used to
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change into a directory with a cd command.
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This is why a lot of times on
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directories you may see the octal notation 755
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because that gives the group and
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other the permissions to read and execute,
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which is really just to change into
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that directory to see the files inside the directory.
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Now just like we saw with the previous slide,
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we can resolve issues with chown and
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chmod as needed and appropriate.
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With that, we've reached the end of this lesson.
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In this lesson, we covered the file and
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directory permissions issues that
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a user is likely to encounter,
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and then we saw some of the tools that we can use to
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identify or resolve these types of issues.
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For example, we can use the list commands,
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ls-al for file permissions or
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ls-ld for directory permissions to view those,
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and if we need to change file or directory ownership,
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we can do that with the change owner or
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chown command and we can change
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file or directory permissions with
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change mode or chmod command as I like to call it.
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Thanks so much for being here and I look
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forward to seeing you in the next lesson.
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