File Permissions and Ownership Flashcards

What does 'chmod g-w file.txt' do?

Answer: Removes write permission from the group

The minus sign in symbolic notation removes the specified permission; g-w removes write from the group.

A new file is created while umask is 0027. What are the resulting file permissions?

Answer: 640 (rw-r-----)

Files start at 0666; 0666 - 0027 = 0640, which is rw-r-----.

Which command shows the numeric (octal) permissions of a file?

Answer: stat file.txt

The stat command displays detailed file information including octal permissions.

What does SGID do when set on a directory?

Answer: New files in the directory inherit the directory's group

SGID on a directory causes newly created files to inherit the directory's group instead of the creator's primary group.

User 'root' owns a file with permissions ----------. Can root read the file?

Answer: Yes, root bypasses permission checks

Root (UID 0) bypasses DAC permission checks and can read, write, and execute any file.

Which permission string indicates a directory with SGID set and execute permission for all?

Answer: drwxr-sr-x

Lowercase 's' in the group execute position (drwxr-sr-x) means SGID is set and execute is enabled for the group.

What happens when you use 'chmod = r file.txt' (symbolic assignment)?

Answer: Sets read permission for all; clears write and execute for all

Using '=' with no class prefix applies to all classes and sets exactly those permissions, clearing all others.