LPI Linux Essentials Practice Exam

The command that allows you to view the kernel ring buffer and check for newly added hardware is a combination of `dmesg` followed by a pipe to `less`. This command retrieves messages from the kernel's logging buffer, known as the kernel ring buffer, which contains crucial information about hardware events, system initialization messages, and other diagnostics.

When a new hardware device is connected, the kernel records messages related to the detection and configuration of that device in the ring buffer. By using `dmesg | less`, you can conveniently view these messages, scrolling through the output as needed to focus on the most recent entries. This is particularly useful because the messages can often be lengthy, and `less` allows for easier navigation.

The other commands provided have different functionalities: `cat /proc/kmsg` could also show kernel messages but is less commonly used than `dmesg` for this purpose and lacks the user-friendly navigation option that `less` provides. `lsmod` is used to list the currently loaded kernel modules, which doesn't directly show the kernel messages or new hardware detection. Lastly, `hwinfo` is a utility for displaying detailed information about hardware but does not specifically output the kernel ring buffer.