diff --git a/062-spawning-processes/spawning-processes.go b/062-spawning-processes/spawning-processes.go
index 44ac4b7..3fe1626 100644
--- a/062-spawning-processes/spawning-processes.go
+++ b/062-spawning-processes/spawning-processes.go
@@ -16,3 +16,4 @@ func main() {
 }
 
 // todo: full command lines with bash
+// todo: piping in stdin
diff --git a/tool/generate.go b/tool/generate.go
index bbf10e5..b8316eb 100644
--- a/tool/generate.go
+++ b/tool/generate.go
@@ -1,30 +1,54 @@
+// Generate HTTML document form a Go source file.
+
 package main
 
 import (
     "os"
     "os/exec"
+    "io/ioutil"
     "fmt"
 )
 
+// Just be sure to blow up on non-nil errors.
 func check(err error) {
     if err != nil {
         panic(err)
     }
 }
 
-func main() {
-    var err error
+func markdown(path, source string) string {
+    cmd := exec.Command(path)
+    in, err := cmd.StdinPipe()
+    check(err)
+    out, err := cmd.StdoutPipe()
+    check(err)
+    err = cmd.Start()
+    check(err)
+    in.Write([]byte(source))
+    check(err)
+    err = in.Close()
+    check(err)
+    bytes, err := ioutil.ReadAll(out)
+    check(err)
+    err = cmd.Wait()
+    check(err)
+    return string(bytes)
+}
 
+func main() {
     // Accept exactly 1 argument - the input filename.
     if len(os.Args) != 2 {
         fmt.Fprintln(os.Stderr, "Usage: tool/generate input.go > output.html")
         os.Exit(1)
     }
 
-    // Ensure that we have `markdown` and `pygmentize` binaries.
+    // Ensure that we have `markdown` and `pygmentize`,
+    // binaries, remember their paths.
     markdownPath, err := exec.LookPath("markdown"); 
     check(err)
-    pygmentizePath, err := exec.LookPath("pygmentize")
-    check(err)
-    fmt.Println(markdownPath, pygmentizePath)
+    fmt.Print(markdown(markdownPath, "## wat"))
+    // pygmentizePath, err := exec.LookPath("pygmentize")
+    // check(err)
+
+    // 
 }