Markdown comments syntax: Comments that won’t appear in generated output

Markdown FAQ: How do I create comments in Markdown? Especially comments that won’t appear in the generated output.

Part 1 of my answer is that technically there is no way — or at least no standard way — to create comments in Markdown documents, other than to use HTML comments like this:

Mac OS X: Unix sed commands I use to clean MacDown HTML output alvin June 13, 2015 - 1:58pm

FWIW, this is the source code for a sed script I use on my Mac OS X system to convert HTML output generated by MacDown into a format I need. MacDown generates some extra “cruft” that I don’t need, so I use these sed commands to clean up that HTML output: