pty-test.go

package main

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path"
	"sync"
	"syscall"

	"github.com/kr/pty"
)

func main() {
	wd, _ := os.Getwd()
	c := exec.Command(path.Join(wd, "pty-test.sh"))
	c.Dir = wd
	c.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

	f, err := pty.Start(c)
	if err != nil {
		panic(err)
	}

	var wg sync.WaitGroup
	wg.Add(1)

	var buffer bytes.Buffer

	go func() {
		_, err = io.Copy(&buffer, f)
		if e, ok := err.(*os.PathError); ok && e.Err == syscall.EIO {
			// We can safely ignore this error, because it's just
			// the PTY telling us that it closed successfully. See:
			// https://github.com/buildkite/agent/pull/34#issuecomment-46080419
			err = nil
		}

		wg.Done()
	}()

	c.Wait()
	wg.Wait()

	fmt.Printf(buffer.String())
}

pty-test.sh

#!/bin/bash

echo "Oh hai there!"