TestOut Linux Pro Practice Test 2025 – Complete Exam Prep Guide

Using the command `chmod 660` on a file assigns specific permissions to the user and group while denying any permissions to others. In this command, the number `6` corresponds to read and write permissions (4 for read and 2 for write) for both the user and the group, which totals 6 (4 + 2). The `0` at the end signifies that no permissions are granted to others.

Therefore, when `chmod 660` is applied, the user has both the ability to read and modify the file, the group has the same read and write permissions, and others are completely restricted from any access. This permission setting is often used for files where collaboration is needed among a specific group of users while ensuring that no one else can access the sensitive information.

The other options do not accurately describe the permissions given by `chmod 660`, as they include different permissions or incorrect combinations that do not match the intended access controls established by this command.