Markdown → AsciiDoc

AsciiDoc sits between Markdown and DocBook: it stays comfortable to read as plain text while carrying features Markdown lacks out of the box — file includes, attributes, cross-references, admonitions. It is the standard documentation format at Red Hat, at Spring and across much of the Java ecosystem, which makes this conversion a frequent step in project migrations.

Paste the Markdown and receive AsciiDoc. Headings swap the hash for an equals sign, keeping the level count; a hyphen list becomes an asterisk list; bold goes from double asterisk to single and italic from single asterisk to underscore, which is the inversion that most confuses people moving between the two; links reverse their order, with the address coming before the bracketed text; and a fenced code block becomes the four-hyphen delimiter.

The conversion is line by line, so it covers the body of a README well and leaves out anything depending on structure: tables, footnotes and nested blocks. It is worth checking the result when the source contains a stray asterisk mid-sentence — the emphasis swap runs on regular expressions, and a literal asterisk can be mistaken for markup.