hugo-theme-bootstrap4-blog/layouts/_default/single.html

{{ define "title" }}{{ .Title }} – {{ .Site.Title }}{{ end }}
{{ define "main" }}
      <article class="blog-post">
        <h2 class="blog-post-title"><a href="{{ .Permalink }}" title="{{ .Title }}">{{ .Title }}</a></h2>
        <p class="blog-post-meta"><time datetime="{{ .Date }}">{{ .Date.Format .Site.Params.date_format }}</time> by <a href="#">{{ .Params.author | default .Site.Params.author }}</a></p>
        {{ .Content }}
      </article> <!-- /.blog-post -->
{{ end }}