A sitemap is basically a map of all of the pages within a specific domain. They are used by search engines and other tools to inform them of all of the pages on your domain.
go run cmd/sitemap-builder/main.go // runs the program with default values
go run cmd/sitemap-builder/main.go --depth [MAX_DEPTH] --url [SOME_URL] // runs the program with a given max depth and url
go run cmd/sitemap-builder/main.go --help // shows information about optional params