When typing answers in an edit-box of the TeX-LaTeX-StackExchange website, which is based on markdown, then from time to time I introduce control-sequence-tokens/sequences of inline-code not via nesting between backticks as in `\macro` but via nesting between HTML-tags <code> and </code> as in <code>\macro</code>. Usually this yields \macro, i.e., the leading backslash \ of the phrase \macro is present.

But when I do this with control-sequence-tokens whose name's first character is @, then the preceding backslash doesn't show up:

<code>\@currenvir</code> yields: @currenvir.

(The phrase \@currenvir is between HTML-tags <code> and </code> and as far as I know neither the backslash nor @ is a special/reserved character in HTML.)


Why does the preceding backslash not show up in the output at the TeX-LaTeX-StackExchange website if in my markdown/HTML-input it is trailed by @?

Am I overlooking some subtle rule regarding syntax of markdown-input or HTML-input or HTML-inside-markdown-input?
If not: Is this a bug?

In case things render differently on different browsers here is a screenshot of what I get when viewing with Chromium under Debian Linux:

enter image description here

  • 1
  • @samcarter_is_at_topanswers.xyz The answer in that link says that with <pre><code>...</code></pre> you need to encode html-entities yourself, but it doesn't specify which characters (besides characters that are special/reserved in HTML) need to be encoded/escaped. Commented Jul 2, 2021 at 18:01

1 Answer 1


The markdown backtick syntax does not only the formatting like the HTML <code> block, but it also escapes special characters, so a \ or a < or > have no special meaning. Inside a <code> block this escaping does not happen, so a backslash introduces an escape sequence. To have a backslash you need an escaped backslash, thus: <code>\\@currenvir</code>, which renders as \@currenvir. You can see the same thing with other non-alphanumeric characters like "!@#$%&*()_+=-'?/<> (in the source of this answer, all of those are preceded by a backslash).

That's also what you have to use when you want to type </code> outside of a backtick pair (or a markdown code block): <code>\</code\></code> renders as </code>, but without the backslashes it would render as  (an empty HTML <code> block, plus a stray </code>).

  • I am a bit confused now: Looking things up in HTML-reference I didn't find backslash to be a special character in HTML. But it is a special character in markdown. Does this mean with HTML inside markdown besides special html-characters you also need to escape special markdown-characters? Commented Jul 2, 2021 at 13:27
  • 2
    @UlrichDiez I believe so, yes. < and > are special for HTML, so you have to escape them (usually with &lt; and &gt;, but here \< and \> also work), but since the edit box for stackexchange is officially markdown, rather than HTML, it makes sense that the backslash is only special for markdown and needs escaping. Commented Jul 2, 2021 at 13:34

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .