How to Use the arch Command to Find Your Machine Architecture in Linux

When you are preparing to download compiled software for a Linux machine, or writing a bash script that needs to run on multiple different servers, you must know the exact hardware architecture of the machine you are currently logged into. Downloading a 64-bit software package for a 32-bit system, or an x86 package for an ARM processor, will result in immediate execution failures. To instantly print your machine’s hardware architecture, you should use the arch command.

How the arch Command Works

The arch command is an incredibly simple, single-purpose utility found on almost all Linux distributions. It is technically a legacy wrapper script; under the hood, running arch is functionally identical to running uname -m (which prints the machine hardware name). However, because arch is shorter and easier to remember, it remains highly popular among system administrators.

Basic Usage and Understanding Output

To determine your system’s architecture, simply type the command into your terminal and press Enter.

arch

The command accepts no complex flags and will instantly output a single short string of text representing your CPU architecture. Here is what the most common outputs actually mean:

• x86_64: This is the most common output on modern desktop PCs, laptops, and enterprise servers. It indicates that you are running a standard 64-bit operating system on an Intel or AMD processor.
• i686 (or i386): If you see this output, you are running a much older 32-bit operating system. Modern software (like Google Chrome or recent Docker releases) often no longer supports this architecture.
• aarch64 (or arm64): This indicates a 64-bit ARM architecture. You will typically see this output if you are logged into a modern Raspberry Pi, an Apple Silicon Mac running a Linux virtual machine, or an ARM-based AWS Graviton cloud server.
• armv7l: This indicates an older 32-bit ARM processor (common on older Raspberry Pi models or embedded IoT devices).

Using arch in Automation Scripts

Because the arch command outputs a clean, highly predictable string with no extra formatting, it is perfect for conditional logic in bash scripts. For example, if you are writing an installation script, you can use the output of arch to automatically determine which version of a binary to download via wget:

if [ "$(arch)" == "x86_64" ]; then
    echo "Downloading 64-bit Intel/AMD package..."
    # wget command here
elif [ "$(arch)" == "aarch64" ]; then
    echo "Downloading 64-bit ARM package..."
    # wget command here
fi