arch

arch prints the machine's hardware architecture — the kind of processor the system runs on.

arch

$ arch
x86_64

That is the whole command. It takes no options and prints a single name.

arch prints exactly what uname -m prints. It exists as a short, obvious name for the one question "what architecture is this?" — convenient in a script that picks an architecture-specific path.

Exit status #

arch returns 0, or 1 if the architecture could not be determined.