added lastmod date after slash in the post header if available.

README.md

@@ -268,6 +268,7 @@ These options can be set from a page [frontmatter](https://gohugo.io/content-man
 |:-------------------- | ------------------ | ---------------- |
 | title                | string             | N/A              |
 | date                 | date               | N/A              |
+| lastmod              | date               | N/A              |
 | description          | string             | N/A              |
 | keywords             | array of strings   | yes              |
 | introDescription     | string             | yes              |
@@ -291,6 +292,8 @@ These options can be set from a page [frontmatter](https://gohugo.io/content-man
 | comments             | boolean            | yes              |
 | enableMathNotation   | boolean            | yes              |
 | showDate             | boolean            | N/A              |
+| showLastmod          | boolean            | N/A              |
+| lastmodSeparator     | string             | N/A              |
 | showShare            | boolean            | N/A              |
 | showReadTime         | boolean            | N/A              |
 | sidebar              | boolean            | N/A              |

layouts/partials/post-meta.html

@@ -1,5 +1,7 @@
 {{- $showShare := ne (.Param "showshare") false }}
 {{- $showDate := ne (.Param "showdate") false }}
+{{- $showLastmod := default false (.Param "showLastmod") }}
+{{- $lastmodSeparator := default "/" (.Param "lastmodSeparator") }}
 {{- $showReadTime := ne (.Param "showreadtime") false }}
 {{- $showPostMeta := or ($showShare) ($showDate) ($showReadTime) (isset .Params "tags") }}
 {{- $scratch := newScratch }}
@@ -11,6 +13,10 @@
     <span>{{ partial "sprite" (dict "icon" "calendar") }}</span>
     <span class="post_date">
       {{ .Date.Format (default "Jan 2, 2006" $.Site.Params.dateFormat) -}}
+      {{ if (and $showLastmod (ne .Date .Lastmod)) }}
+        {{ $lastmodSeparator }} <time datetime="{{ .Lastmod.Format "Mon Jan 10 17:13:38 2020 -0700" }}">
+        {{ .Lastmod.Format (default "Jan 2, 2006" $.Site.Params.dateFormat) }}</time>
+      {{ end }}	  
     </span>
     {{- $scratch.Set "writeSeparator" true }}
   {{- end }}