diff --git a/cmd/present2md/main.go b/cmd/present2md/main.go
new file mode 100644
index 0000000000..86c0286627
--- /dev/null
+++ b/cmd/present2md/main.go
@@ -0,0 +1,468 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Present2md converts legacy-syntax present files to Markdown-syntax present files.
+//
+// Usage:
+//
+//	present2md [-w] [file ...]
+//
+// By default, present2md prints the Markdown-syntax form of each input file to standard output.
+// If no input file is listed, standard input is used.
+//
+// The -w flag causes present2md to update the files in place, overwriting each with its
+// Markdown-syntax equivalent.
+//
+// Examples
+//
+//	present2md your.article
+//	present2md -w *.article
+//
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/url"
+	"os"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"golang.org/x/tools/present"
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: present2md [-w] [file ...]\n")
+	os.Exit(2)
+}
+
+var (
+	writeBack  = flag.Bool("w", false, "write conversions back to original files")
+	exitStatus = 0
+)
+
+func main() {
+	log.SetPrefix("present2md: ")
+	log.SetFlags(0)
+	flag.Usage = usage
+	flag.Parse()
+
+	args := flag.Args()
+	if len(args) == 0 {
+		if *writeBack {
+			log.Fatalf("cannot use -w with standard input")
+		}
+		convert(os.Stdin, "stdin", false)
+		return
+	}
+
+	for _, arg := range args {
+		f, err := os.Open(arg)
+		if err != nil {
+			log.Print(err)
+			exitStatus = 1
+			continue
+		}
+		err = convert(f, arg, *writeBack)
+		f.Close()
+		if err != nil {
+			log.Print(err)
+			exitStatus = 1
+		}
+	}
+	os.Exit(exitStatus)
+}
+
+// convert reads the data from r, parses it as legacy present,
+// and converts it to Markdown-enabled present.
+// If any errors occur, the data is reported as coming from file.
+// If writeBack is true, the converted version is written back to file.
+// If writeBack is false, the converted version is printed to standard output.
+func convert(r io.Reader, file string, writeBack bool) error {
+	data, err := ioutil.ReadAll(r)
+	if err != nil {
+		return err
+	}
+	if bytes.HasPrefix(data, []byte("# ")) {
+		return fmt.Errorf("%v: already markdown", file)
+	}
+
+	doc, err := present.Parse(bytes.NewReader(data), file, 0)
+	if err != nil {
+		return err
+	}
+
+	// Title and Subtitle, Time, Tags.
+	var md bytes.Buffer
+	fmt.Fprintf(&md, "# %s\n", doc.Title)
+	if doc.Subtitle != "" {
+		fmt.Fprintf(&md, "%s\n", doc.Subtitle)
+	}
+	if !doc.Time.IsZero() {
+		fmt.Fprintf(&md, "%s\n", doc.Time.Format("2 Jan 2006"))
+	}
+	if len(doc.Tags) > 0 {
+		fmt.Fprintf(&md, "Tags: %s\n", strings.Join(doc.Tags, ", "))
+	}
+
+	// Summary, defaulting to first paragraph of section.
+	// (Summaries must be explicit for Markdown-enabled present,
+	// and the expectation is that they will be shorter than the
+	// whole first paragraph. But this is what the blog does today.)
+	if strings.HasSuffix(file, ".article") && len(doc.Sections) > 0 {
+		for _, elem := range doc.Sections[0].Elem {
+			text, ok := elem.(present.Text)
+			if !ok || text.Pre {
+				// skip everything but non-text elements
+				continue
+			}
+			fmt.Fprintf(&md, "Summary:")
+			for i, line := range text.Lines {
+				fmt.Fprintf(&md, " ")
+				printStyled(&md, line, i == 0)
+			}
+			fmt.Fprintf(&md, "\n")
+			break
+		}
+	}
+
+	// Authors
+	for _, a := range doc.Authors {
+		fmt.Fprintf(&md, "\n")
+		for _, elem := range a.Elem {
+			switch elem := elem.(type) {
+			default:
+				// Can only happen if this type switch is incomplete, which is a bug.
+				log.Fatalf("%s: unexpected author type %T", file, elem)
+			case present.Text:
+				for _, line := range elem.Lines {
+					fmt.Fprintf(&md, "%s\n", markdownEscape(line, true))
+				}
+			case present.Link:
+				fmt.Fprintf(&md, "%s\n", markdownEscape(elem.Label, true))
+			}
+		}
+	}
+
+	// Invariant: the output ends in non-blank line now,
+	// and after printing any piece of the file below,
+	// the output should still end in a non-blank line.
+	// If a blank line separator is needed, it should be printed
+	// before the block that needs separating, not after.
+
+	if len(doc.TitleNotes) > 0 {
+		fmt.Fprintf(&md, "\n")
+		for _, line := range doc.TitleNotes {
+			fmt.Fprintf(&md, ": %s\n", line)
+		}
+	}
+
+	if len(doc.Sections) == 1 && strings.HasSuffix(file, ".article") {
+		// Blog drops section headers when there is only one section.
+		// Don't print a title in this case, to make clear that it's being dropped.
+		fmt.Fprintf(&md, "\n##\n")
+		printSectionBody(file, 1, &md, doc.Sections[0].Elem)
+	} else {
+		for _, s := range doc.Sections {
+			fmt.Fprintf(&md, "\n")
+			fmt.Fprintf(&md, "## %s\n", markdownEscape(s.Title, false))
+			printSectionBody(file, 2, &md, s.Elem)
+		}
+	}
+
+	if !writeBack {
+		os.Stdout.Write(md.Bytes())
+		return nil
+	}
+	return ioutil.WriteFile(file, md.Bytes(), 0666)
+}
+
+func printSectionBody(file string, depth int, w *bytes.Buffer, elems []present.Elem) {
+	for _, elem := range elems {
+		switch elem := elem.(type) {
+		default:
+			// Can only happen if this type switch is incomplete, which is a bug.
+			log.Fatalf("%s: unexpected present element type %T", file, elem)
+
+		case present.Text:
+			fmt.Fprintf(w, "\n")
+			lines := elem.Lines
+			for len(lines) > 0 && lines[0] == "" {
+				lines = lines[1:]
+			}
+			if elem.Pre {
+				for _, line := range strings.Split(strings.TrimRight(elem.Raw, "\n"), "\n") {
+					if line == "" {
+						fmt.Fprintf(w, "\n")
+					} else {
+						fmt.Fprintf(w, "\t%s\n", line)
+					}
+				}
+			} else {
+				for _, line := range elem.Lines {
+					printStyled(w, line, true)
+					fmt.Fprintf(w, "\n")
+				}
+			}
+
+		case present.List:
+			fmt.Fprintf(w, "\n")
+			for _, item := range elem.Bullet {
+				fmt.Fprintf(w, "  - ")
+				for i, line := range strings.Split(item, "\n") {
+					if i > 0 {
+						fmt.Fprintf(w, "    ")
+					}
+					printStyled(w, line, false)
+					fmt.Fprintf(w, "\n")
+				}
+			}
+
+		case present.Section:
+			fmt.Fprintf(w, "\n")
+			sep := " "
+			if elem.Title == "" {
+				sep = ""
+			}
+			fmt.Fprintf(w, "%s%s%s\n", strings.Repeat("#", depth+2), sep, markdownEscape(elem.Title, false))
+			printSectionBody(file, depth+1, w, elem.Elem)
+
+		case interface{ PresentCmd() string }:
+			// If there are multiple present commands in a row, don't print a blank line before the second etc.
+			b := w.Bytes()
+			sep := "\n"
+			if len(b) > 0 {
+				i := bytes.LastIndexByte(b[:len(b)-1], '\n')
+				if b[i+1] == '.' {
+					sep = ""
+				}
+			}
+			fmt.Fprintf(w, "%s%s\n", sep, elem.PresentCmd())
+		}
+	}
+}
+
+func markdownEscape(s string, startLine bool) string {
+	var b strings.Builder
+	for i, r := range s {
+		switch {
+		case r == '#' && i == 0,
+			r == '*',
+			r == '_',
+			r == '<' && (i == 0 || s[i-1] != ' ') && i+1 < len(s) && s[i+1] != ' ',
+			r == '[' && strings.Contains(s[i:], "]("):
+			b.WriteRune('\\')
+		}
+		b.WriteRune(r)
+	}
+	return b.String()
+}
+
+// Copy of ../../present/style.go adjusted to produce Markdown instead of HTML.
+
+/*
+	Fonts are demarcated by an initial and final char bracketing a
+	space-delimited word, plus possibly some terminal punctuation.
+	The chars are
+		_ for italic
+		* for bold
+		` (back quote) for fixed width.
+	Inner appearances of the char become spaces. For instance,
+		_this_is_italic_!
+	becomes
+		<i>this is italic</i>!
+*/
+
+func printStyled(w *bytes.Buffer, text string, startLine bool) {
+	w.WriteString(font(text, startLine))
+}
+
+// font returns s with font indicators turned into HTML font tags.
+func font(s string, startLine bool) string {
+	if !strings.ContainsAny(s, "[`_*") {
+		return markdownEscape(s, startLine)
+	}
+	words := split(s)
+	var b bytes.Buffer
+Word:
+	for w, word := range words {
+		words[w] = markdownEscape(word, startLine && w == 0) // for all the continue Word
+		if len(word) < 2 {
+			continue Word
+		}
+		if link, _ := parseInlineLink(word); link != "" {
+			words[w] = link
+			continue Word
+		}
+		const marker = "_*`"
+		// Initial punctuation is OK but must be peeled off.
+		first := strings.IndexAny(word, marker)
+		if first == -1 {
+			continue Word
+		}
+		// Opening marker must be at the beginning of the token or else preceded by punctuation.
+		if first != 0 {
+			r, _ := utf8.DecodeLastRuneInString(word[:first])
+			if !unicode.IsPunct(r) {
+				continue Word
+			}
+		}
+		open, word := markdownEscape(word[:first], startLine && w == 0), word[first:]
+		char := word[0] // ASCII is OK.
+		close := ""
+		switch char {
+		default:
+			continue Word
+		case '_':
+			open += "_"
+			close = "_"
+		case '*':
+			open += "**"
+			close = "**"
+		case '`':
+			open += "`"
+			close = "`"
+		}
+		// Closing marker must be at the end of the token or else followed by punctuation.
+		last := strings.LastIndex(word, word[:1])
+		if last == 0 {
+			continue Word
+		}
+		if last+1 != len(word) {
+			r, _ := utf8.DecodeRuneInString(word[last+1:])
+			if !unicode.IsPunct(r) {
+				continue Word
+			}
+		}
+		head, tail := word[:last+1], word[last+1:]
+		b.Reset()
+		var wid int
+		for i := 1; i < len(head)-1; i += wid {
+			var r rune
+			r, wid = utf8.DecodeRuneInString(head[i:])
+			if r != rune(char) {
+				// Ordinary character.
+				b.WriteRune(r)
+				continue
+			}
+			if head[i+1] != char {
+				// Inner char becomes space.
+				b.WriteRune(' ')
+				continue
+			}
+			// Doubled char becomes real char.
+			// Not worth worrying about "_x__".
+			b.WriteByte(char)
+			wid++ // Consumed two chars, both ASCII.
+		}
+		text := b.String()
+		if close == "`" {
+			for strings.Contains(text, close) {
+				open += "`"
+				close += "`"
+			}
+		} else {
+			text = markdownEscape(text, false)
+		}
+		words[w] = open + text + close + tail
+	}
+	return strings.Join(words, "")
+}
+
+// split is like strings.Fields but also returns the runs of spaces
+// and treats inline links as distinct words.
+func split(s string) []string {
+	var (
+		words = make([]string, 0, 10)
+		start = 0
+	)
+
+	// appendWord appends the string s[start:end] to the words slice.
+	// If the word contains the beginning of a link, the non-link portion
+	// of the word and the entire link are appended as separate words,
+	// and the start index is advanced to the end of the link.
+	appendWord := func(end int) {
+		if j := strings.Index(s[start:end], "[["); j > -1 {
+			if _, l := parseInlineLink(s[start+j:]); l > 0 {
+				// Append portion before link, if any.
+				if j > 0 {
+					words = append(words, s[start:start+j])
+				}
+				// Append link itself.
+				words = append(words, s[start+j:start+j+l])
+				// Advance start index to end of link.
+				start = start + j + l
+				return
+			}
+		}
+		// No link; just add the word.
+		words = append(words, s[start:end])
+		start = end
+	}
+
+	wasSpace := false
+	for i, r := range s {
+		isSpace := unicode.IsSpace(r)
+		if i > start && isSpace != wasSpace {
+			appendWord(i)
+		}
+		wasSpace = isSpace
+	}
+	for start < len(s) {
+		appendWord(len(s))
+	}
+	return words
+}
+
+// parseInlineLink parses an inline link at the start of s, and returns
+// a rendered Markdown link and the total length of the raw inline link.
+// If no inline link is present, it returns all zeroes.
+func parseInlineLink(s string) (link string, length int) {
+	if !strings.HasPrefix(s, "[[") {
+		return
+	}
+	end := strings.Index(s, "]]")
+	if end == -1 {
+		return
+	}
+	urlEnd := strings.Index(s, "]")
+	rawURL := s[2:urlEnd]
+	const badURLChars = `<>"{}|\^[] ` + "`" // per RFC2396 section 2.4.3
+	if strings.ContainsAny(rawURL, badURLChars) {
+		return
+	}
+	if urlEnd == end {
+		simpleURL := ""
+		url, err := url.Parse(rawURL)
+		if err == nil {
+			// If the URL is http://foo.com, drop the http://
+			// In other words, render [[http://golang.org]] as:
+			//   <a href="http://golang.org">golang.org</a>
+			if strings.HasPrefix(rawURL, url.Scheme+"://") {
+				simpleURL = strings.TrimPrefix(rawURL, url.Scheme+"://")
+			} else if strings.HasPrefix(rawURL, url.Scheme+":") {
+				simpleURL = strings.TrimPrefix(rawURL, url.Scheme+":")
+			}
+		}
+		return renderLink(rawURL, simpleURL), end + 2
+	}
+	if s[urlEnd:urlEnd+2] != "][" {
+		return
+	}
+	text := s[urlEnd+2 : end]
+	return renderLink(rawURL, text), end + 2
+}
+
+func renderLink(href, text string) string {
+	text = font(text, false)
+	if text == "" {
+		text = markdownEscape(href, false)
+	}
+	return "[" + text + "](" + href + ")"
+}