Imagine we’re in our single post template. We’d have access to the .Params.categories Page variable.

{{- with .Params.categories -}}
      <div class="post-categories">
        {{- range . -}}
            {{ $cat := urlize . }}
             {{ with $ctx.Site.GetPage (printf "/%s/%s" "categories" $slug ) }}
                <a class="tag" href="{{ .Permalink }}">{{ .Title }}</a> |
            {{- end }}
        {{- end }}
{{- end -}}

So the first line is our check for some categories:

{{ with .Params.categories }}

And then we loop through the post categories, using the shorthand for the current context

{{ range . }}

And then what we want to do is check to see if there is a page for that current category (you might have tags which aren’t public)

so we define a varable called $cat which is the result of running the current category name through Hugo’s urlize function.

 {{ $cat := urlize . }}

If a page exists then Hugo will output this category using the .Permalink and .Title of the category in the current iteration of the loop.

     {{ with $.Site.GetPage (printf "/%s/%s" "categories" $slug ) }}