archdetect

archdetect [OPTIONS]

--help
    Displays a help message and exits.

--version
    Shows the program version information and exits.

archdetect is a command-line utility primarily used within installer environments, such as the Debian or Ubuntu installer (debian-installer), to automatically detect the system's hardware architecture. Its main purpose is to determine the correct architecture string (e.g., "amd64", "i386", "armhf", "arm64", "powerpc") for the system it's running on. This information is crucial for selecting the appropriate kernel, packages, and system components during the installation process. The command gathers architecture details from various sources, including the running kernel's information (like /proc/cpuinfo), BIOS data, and other system-specific heuristics, to provide a reliable architecture identification. It typically outputs the detected architecture string to standard output, making it easy for scripts within the installer to consume this information and proceed with architecture-specific tasks. While not commonly used by end-users post-installation, it plays a vital role in ensuring a smooth and correct operating system deployment.

archdetect is not a general-purpose system information tool for end-users; its primary design and usage are within operating system installer environments (e.g., Debian/Ubuntu's debian-installer). It relies on kernel and BIOS information, and its output is specifically formatted for consumption by installer scripts, typically just outputting the architecture string. For post-installation architecture queries, commands like uname -m or dpkg-architecture -qDEB_HOST_ARCH are more appropriate and versatile. Its behavior and available "options" are heavily tied to its role in the installation process and may vary slightly across different installer versions or distributions.

In installer scripts, archdetect is often called, and its output is captured into a variable, which then dictates subsequent actions like which kernel image to load or which package repositories to use. A common invocation is archdetect auto, which attempts to automatically determine the architecture.

Example:
ARCH=$(archdetect auto)
This command would set the ARCH shell variable to the detected architecture string (e.g., "amd64").

When successful, archdetect typically prints a single line to standard output containing the detected Debian architecture string (e.g., "amd64", "i386", "arm64"). No other output is usually provided on standard output unless an error occurs or a help/version flag is used.

archdetect has been a fundamental component of the Debian Installer (debian-installer) since its early development. It was designed to provide a robust and automated way for the installer to identify the target system's architecture, thereby simplifying the multi-architecture support crucial for Debian. Its evolution has been closely tied to the debian-installer project, adapting to new hardware platforms and kernel changes to ensure accurate detection across a wide range of systems. Before archdetect, manual architecture selection or less sophisticated detection methods were often used, making the installation process more prone to errors or requiring more user intervention.

uname(1), dpkg-architecture(1)