LCA User & Permission Management 3

Question 1

Which command displays the numeric UID and GID of the current user along with all supplementary group memberships?

Accepted Answer

id

Answer

The id command shows the current user's UID, primary GID, and all supplementary group IDs.

Question 2

What does the command 'newgrp developers' accomplish?

Accepted Answer

Starts a subshell with developers as the effective primary group

Answer

newgrp opens a new shell session where the specified group becomes the user's effective primary group for that session.

Question 3

Which useradd option specifies a comment (GECOS field) such as the user's full name?

Accepted Answer

-c

Answer

The -c option sets the GECOS/comment field, typically used for the user's full name or description.

Question 4

A file has permissions 664. What is the symbolic equivalent for the 'others' portion?

Accepted Answer

r--

Answer

The last octal digit 4 equals binary 100, which maps to read-only (r--).

Question 5

Which file defines default settings (like UMASK and home directory skeleton path) used by useradd?

Accepted Answer

/etc/default/useradd

Answer

/etc/default/useradd stores defaults for the useradd command such as SHELL, HOME, INACTIVE, and EXPIRE.

(LCA) Certified Linux Administrator Practice Test