NixOS
NixOS is an independently developed GNU/Linux distribution that aims to improve the state of the art in system configuration management. In NixOS, the entire operating system, including the kernel, applications, system packages and configuration files, are built by the Nix package manager.
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Red Hat Enterprise Linux
Red Hat Enterprise Linux (RHEL) is a Linux distribution developed by Red Hat and targeted toward the commercial market. Red Hat Enterprise Linux is released in server editions for x86, x86_64, Itanium, PowerPC and IBM System z architectures, and desktop editions for x86 and x86_64 processors.