The correct option is snapshot. Btrfs, a modern file system for Linux, provides a feature that allows for creating a readable/writable "snapshot" of a subvolume. Snapshots are a powerful tool for data protection and efficient use of disk space.

In Linux, the jobs command is used to display the status of jobs in the current session. It provides information about background processes or jobs started within the current shell session.

The ip command in Linux can be used to manipulate or display IP routing tables. It's a powerful and versatile tool for configuring network interfaces, routes, tunnels, and more. Unlike older commands like route and ifconfig, ip is considered a modern and more comprehensive replacement.

To trace the system calls made by an application on Linux, you would use the strace tool. It provides detailed information about the system calls, signals, and other interactions the application has with the operating system, which is valuable for debugging and analysis.

OpenVPN is considered highly secure and commonly used in Linux. It's an open-source VPN protocol that provides strong encryption and is widely trusted for creating secure network connections.

The "passwd" command in Linux allows you to enforce a user to change their password upon the next login. This is often used for security reasons, such as when a user's password has expired.

A common use of do-while loops is for input validation, ensuring that a specific task is performed at least once before checking the condition. The unnecessary iteration might occur because the loop is designed to prompt the user for input before evaluating the condition. An alternative solution could be to use a while loop with the condition checked before the loop, but it wouldn't guarantee at least one execution.

In the early days of web development, there was another language called "LiveScript" that was developed almost simultaneously with JavaScript. Although they had similar names, they were different languages. Eventually, LiveScript was renamed to JavaScript.

The mechanism that allows you to use the structure of a class and alter it for use in another class is known as "Inheritance." Inheritance in JavaScript is achieved through the prototype chain, where a child class can inherit properties and methods from a parent class, allowing for code reuse and extension.

The keyword "new" in JavaScript is used to instantiate an object from a class constructor. When you use "new" followed by a class constructor, it creates a new instance of that class, allowing you to work with objects that have the properties and methods defined in the class. It doesn't create a class, declare a variable, or define a function.