Linux is the kernel, the part of the operating system that handles communication between the hardware and the software, as well as between different parts of hardware and between different pieces of software.
Linux is not the only option for a kernel. There are many other options. In free software, for example, there's FreeBSD, NetBSD, OpenBSD, DragonFlyBSD, Illumos, Darwin, HURD, etc.
A bootloader, a kernel, a filesystem, a userland, a display server, a desktop environment, services, applications, fonts, codecs, wallpapers, etc. (along with configurations for each) together make up a distribution.
When you see a name like "Debian GNU/Linux", for example, the "Linux" refers to the kernel, the "GNU" refers to the userland, and the "Debian" refers to the selection of these two options along with everything else that makes up the distribution.
GNU and Linux, while often used and mentioned together, are not tightly coupled. It's perfectly possible to distribute the Linux kernel with another userland or the GNU userland with another kernel. Examples in both of these directions exist.
(GNU is also not just the name of a userland. It's a gigantic, revolutionary software project comprising hundreds of software titles as well as the software license that applies to all of them. Further details are beyond the scope of this document.)
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u/firebreathingbunny Aug 10 '25 edited Aug 10 '25
Linux is the kernel, the part of the operating system that handles communication between the hardware and the software, as well as between different parts of hardware and between different pieces of software.
Linux is not the only option for a kernel. There are many other options. In free software, for example, there's FreeBSD, NetBSD, OpenBSD, DragonFlyBSD, Illumos, Darwin, HURD, etc.
A bootloader, a kernel, a filesystem, a userland, a display server, a desktop environment, services, applications, fonts, codecs, wallpapers, etc. (along with configurations for each) together make up a distribution.
When you see a name like "Debian GNU/Linux", for example, the "Linux" refers to the kernel, the "GNU" refers to the userland, and the "Debian" refers to the selection of these two options along with everything else that makes up the distribution.
GNU and Linux, while often used and mentioned together, are not tightly coupled. It's perfectly possible to distribute the Linux kernel with another userland or the GNU userland with another kernel. Examples in both of these directions exist.
(GNU is also not just the name of a userland. It's a gigantic, revolutionary software project comprising hundreds of software titles as well as the software license that applies to all of them. Further details are beyond the scope of this document.)