#Underline text in different lightweight markup languages:

Emacs #OrgMode , Muse:
_this_

#DokuWiki:
__this__

#Textile, #Jira
+this+

There is no Markdown syntax for underlined text, but #pandoc's #Markdown reader treats the content of spans with class "underline" or "ul" as #underlined:

[important]{.underline}
[nota bene]{.ul}

#reStructuredText follows the logic that underlined text means that it's a link, so it doesn't have dedicated syntax for (non-link) underlined text either. Support can be added with this syntax

.. role:: underline
:class: underline

:underline:`this`

in combination with a short #LuaFilter

function Span(s)
return s.classes[1] == 'underline' and pandoc.Underline(s.content) or nil
end

#pandoc #rst #underline

@pandoc: The same with SmallCaps. You have to use [Your Text]{.smallcaps} to convert via #pandoc or #zettlr to ICML/IDML/INDD.

@pandoc good to know!

Note however that in a web context underlining plain text is a bad thing to do as people mistake it as a hyperlink.

Maybe thats the reason why most #markdown dialects don't provide that feature upfront.