Which command would you use to view hardware-related messages?

The command used to view hardware-related messages is 'dmesg.' This command reads the kernel ring buffer, which contains messages from the Linux kernel regarding hardware detection and driver activity during system startup and runtime. When you run 'dmesg,' you can see information about devices that were initialized, errors, warnings, or status updates about hardware components. This can be incredibly useful for troubleshooting hardware issues or verifying that devices are recognized by the system.

The other options serve different purposes. 'grep' is a command-line utility that searches for patterns within text files or output but does not directly provide hardware information. 'systemctl' is used to investigate and manage system services in systems that use systemd; it does not deal specifically with hardware messages. 'iwconfig' is a command for configuring wireless network interfaces, focused specifically on wireless networking rather than general hardware messages. Thus, 'dmesg' is the most appropriate command for viewing messages related to hardware.