Linux is an operating system (OS), which is the primary software that a computer uses to execute tasks and communicate directions to its hardware. The operating system that competes the most with Linux is Windows. Linux is a popular and widely-used OS because it is open-source, meaning that it is free to the public, and anyone can modify and customize Linux software as they wish. The reasons to use Linux can vary from developing an app or building a video game to learning how to hack computer systems. As Linux is one of the most popular operating systems, many developers use it to develop their web applications and software programs. This means knowledge of Linux is important for anyone working with computers and software in general. Learning how to work with Linux is a necessary skill for anyone pursuing a career in ethical hacking or penetration testing and a valuable skill for many other software and IT-related career paths.