What does the uname -r command do?

The command uname -r is used to display the kernel version of the Linux operating system. When this command is executed, it provides specific information about the currently running kernel, which includes the major version number and additional details that can indicate patches or specific builds of the kernel. This is useful for administrators and developers when troubleshooting or ensuring compatibility with software, hardware, or other system components that depend on the kernel version.

The other options pertain to different aspects of system information but do not relate to what uname -r specifically provides. For instance, displaying the hostname would typically involve the command hostname, while system architecture can be shown using uname -m. The OS name can usually be viewed using commands such as lsb_release -a or checking the contents of the /etc/os-release file. Each of these commands serves a unique purpose for retrieving various types of system information.