The documentation is clearly not updated. It says on the page https://gohugo.io/getting-started/usage/#the-hugo-command
please add a comment to indicate that without the switch nothing is produce. This is VERY confusing for a somebody to start using Hugo!
@andrewufrank, the post you responded to and the documentation you refer to are on two different topics. The person had asked about using hugo server, and rendering to disk. By default hugo (by itself) writes to the public directory.
If the command on its own is not writing to public for you, there may be another issue, and I recommend you read Requesting Help and edit your post.