010-160 File Permissions and Ownership 3

Question 1

What permission is needed to list the contents of a directory?

Accepted Answer

Read (r)

Answer

Read permission on a directory allows listing its contents with ls.

Question 2

Which command recursively changes ownership of /var/www to user 'www-data'?

Accepted Answer

chown -R www-data /var/www

Answer

chown -R applies the ownership change recursively to all files and subdirectories.

Question 3

What does the SUID bit do when set on an executable file?

Accepted Answer

Runs the file with the owner's privileges

Answer

SUID causes an executable to run with the file owner's effective user ID instead of the caller's.

Question 4

How is the SUID bit represented in ls -l output for a file with execute permission?

Accepted Answer

s in the owner execute position

Answer

A lowercase 's' in the owner execute position means SUID is set and execute is also set.

Question 5

Which octal value sets the sticky bit on a directory along with permissions 755?

Accepted Answer

1755

Answer

The sticky bit is represented by the leading octal digit 1, so 1755 = sticky + rwxr-xr-x.

(010-160) LPI Linux Essentials Practice Test