Some people consider this to be much easier than following the standard Word Press installation and upgrade methods (downloading and unzipping archives, then using FTP to put them on your web host), and this article explains how to do it. Subversion is one of many existing source-code version-control systems; specifically, it is the version-control system that is used by Word Press.
Version-control systems are used by software developers to keep track of their source code and its revisions behind the scenes, and periodically release versions of the software for public use.
Here are the commands (assuming the version you want is 4.9.2): The period at the end of the command is very important - it makes sure that downloaded files from the repository end up in the current directory; leave off that dot and you'll end up creating a new installation directory (which would be called ", then access your blog URL to complete installation, as in the standard Word Press installation instructions.
The next time Word Press releases a new version, you will probably want to upgrade to that version.
To do that, log in and use the Subversion "switch" command (sw) to switch to a new version (assuming the new version is 4.9.2): Doing so will overwrite any changed Word Press-provided files, while leaving any custom or privately owned files, plugins, and themes alone.