0 — Test 605

Correct Answer: C. File 644 (rw-r--r--); directory 755 (rwxr-xr-x)
Explanation: New files start from 666 (no execute bit by default) and directories from 777. The umask bits are removed from those starting values. ALSO KNOW (related points): • What is the numeric (octal) value of the permission string rw-r-----? → 640

Correct Answer: C. Only a file's owner (or root) can delete or rename that file, even though everyone can write to the directory
Explanation: Set it with chmod +t or chmod 1777. ALSO KNOW (related points): • Which command changes both the owner and the group of report.txt to ali and staff? → chown ali:staff report.txt

Correct Answer: D. The program runs with the file owner's privileges (here, root), not the caller's
Explanation: This is how ordinary users can update /etc/shadow through passwd. It appears as an 's' in the owner's execute position.

Correct Answer: D. No; deleting a file requires write (and execute) permission on the directory
Explanation: Deleting removes a directory entry, which is a change to the directory, not to the file itself. ALSO KNOW (related points): • What does chmod u+x,g-w,o= file do? → Adds execute for the owner, removes write from the group, and removes all permissions for others

Correct Answer: D. Entering the directory (cd) and accessing files inside it by name
Explanation: Read (r) on a directory allows listing the names. Creating files requires both w and x. ALSO KNOW (related points): • What does an 's' in a directory's group execute position (setgid) do? → New files created in the directory inherit the directory's group

Correct Answer: A. chown ali:staff report.txt
Explanation: chgrp changes only the group. chmod changes permissions.

Correct Answer: B. The entry is a symbolic link
Explanation: '-' means a regular file, 'd' a directory, 'c' or 'b' a character or block device, 'p' a pipe, and 's' a socket.

Correct Answer: C. Adds execute for the owner, removes write from the group, and removes all permissions for others
Explanation: o= with nothing after the = clears every permission for others.

Correct Answer: D. 640
Explanation: rw- = 6, r-- = 4, --- = 0.

Correct Answer: C. New files created in the directory inherit the directory's group
Explanation: Setgid directories are useful for shared project folders.