Pandoc is a command-line utility that can convert files from one markup format into another.
Pandoc's enhanced version of Markdown includes syntax for footnotes, tables, flexible ordered lists, definition lists, fenced code blocks, superscripts and subscripts, strikeout, metadata blocks, automatic tables of contents, embedded LaTeX math, citations, and Markdown inside HTML block elements. (These enhancements, described further under Pandoc's Markdown, can be disabled using the markdown_strict input or output format.)
In contrast to most existing tools for converting Markdown to HTML, which use regex substitutions, Pandoc has a modular design: it consists of a set of readers, which parse text in a given format and produce a native representation of the document, and a set of writers, which convert this native representation into a target format. Thus, adding an input or output format requires only adding a reader or writer.
Because Pandoc's intermediate representation of a document is less expressive than many of the formats it converts between, one should not expect perfect conversions between every format and every other. Pandoc attempts to preserve the structural elements of a document but not formatting details such as margin size. And some document elements, such as complex tables, may not fit into Pandoc's simple document model. While conversions from Pandoc's Markdown to all formats aspire to be perfect, conversions from formats more expressive than Pandoc's Markdown can be expected to be lossy.