Read, Write, Execute (rwx)

Definition

The three fundamental permissions in Linux. Read (view contents), Write (modify contents), and Execute (run as a program or enter a directory).

Explain Like I'm New

Read: Look but don't touch. Write: You can edit or delete it. Execute: You can run it like an app.

Real World Example

If you look at `ls -l`, you see `rwxr-xr--`. This means the Owner has Read/Write/Execute. The Group has Read/Execute. Everyone else only has Read.

Common Use Cases

•Securing files
•Troubleshooting 'Permission Denied' errors

Interview Questions

basic

What does the 'Execute' permission do if applied to a Directory (folder) instead of a File?

intermediate

If a user has 'Write' permission on a file, but NOT 'Write' permission on the directory containing the file, can they delete the file?

Flash Cards

Question

Execute on a directory?

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Answer

It allows a user to 'enter' the directory using the `cd` command. Without execute permission on a folder, you cannot open it.

Question

Can they delete the file?

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Answer

No! In Linux, deleting a file is actually considered modifying the *directory* that holds the file. You must have Write permission on the parent folder to delete a file inside it.