The ioreg command is a powerful utility on macOS for inspecting the I/O Kit registry. This registry is a hierarchical database that describes all the hardware and software components of the system, including their properties and relationships. Developers and system administrators can use ioreg to understand how devices are connected and configured.
The I/O Kit registry is often referred to as the device tree. The ioreg command allows you to traverse this tree and extract detailed information about each node. This is crucial for debugging hardware issues, understanding driver behavior, and exploring system architecture.
A common use case for ioreg is to find out specific details about the system's firmware, such as the architecture of the EFI firmware. By filtering the output of ioreg, you can pinpoint the exact information you need.
To find out the architecture of the EFI firmware on a Mac, you can use the following command:
ioreg -l -p IODeviceTree | grep firmware-abiThis command lists all I/O Kit registry entries, filters for the IODeviceTree, and then searches for lines containing "firmware-abi" to reveal the firmware's architecture.
For more advanced usage and a deeper understanding of the I/O Kit, consult the official macOS developer documentation. Understanding the structure of the I/O Kit registry can provide invaluable insights into your system's operation.