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LPI

303-300 · Question #65

Which permission bit allows a file to be executed?

The correct answer is C. Execute. Execute (C) is the permission bit that allows a file to be run as a program - without it, even a perfectly written script will be rejected by the OS when you try to launch it. Read (A) only allows viewing file contents; Write (B) only allows modifying them - neither grants the…

Access Control

Question

Which permission bit allows a file to be executed?

Options

  • ARead
  • BWrite
  • CExecute
  • DSetUID

How the community answered

(18 responses)
  • B
    6% (1)
  • C
    94% (17)

Explanation

Execute (C) is the permission bit that allows a file to be run as a program - without it, even a perfectly written script will be rejected by the OS when you try to launch it.

Read (A) only allows viewing file contents; Write (B) only allows modifying them - neither grants the ability to run a file. SetUID (D) is a special permission that runs a file as its owner's identity (e.g., root), but it only matters after execute is already set - it doesn't itself grant execution.

Memory tip: Think R-W-X in order (Read, Write, eXecute) - X is always the third bit and the one that "starts" the file.

Topics

#file permissions#execute bit#unix modes#access control

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