pty

README

pty

Pty is a Go package for using unix pseudo-terminals.

Install

go get github.com/kr/pty

Example

Command

package main

import (
	"github.com/kr/pty"
	"io"
	"os"
	"os/exec"
)

func main() {
	c := exec.Command("grep", "--color=auto", "bar")
	f, err := pty.Start(c)
	if err != nil {
		panic(err)
	}

	go func() {
		f.Write([]byte("foo\n"))
		f.Write([]byte("bar\n"))
		f.Write([]byte("baz\n"))
		f.Write([]byte{4}) // EOT
	}()
	io.Copy(os.Stdout, f)
}

Shell

package main

import (
        "io"
        "log"
        "os"
        "os/exec"
        "os/signal"
        "syscall"

        "github.com/kr/pty"
        "golang.org/x/crypto/ssh/terminal"
)

func test() error {
        // Create arbitrary command.
        c := exec.Command("bash")

        // Start the command with a pty.
        ptmx, err := pty.Start(c)
        if err != nil {
                return err
        }
        // Make sure to close the pty at the end.
        defer func() { _ = ptmx.Close() }() // Best effort.

        // Handle pty size.
        ch := make(chan os.Signal, 1)
        signal.Notify(ch, syscall.SIGWINCH)
        go func() {
                for range ch {
                        if err := pty.InheritSize(os.Stdin, ptmx); err != nil {
                                log.Printf("error resizing pty: %s", err)
                        }
                }
        }()
        ch <- syscall.SIGWINCH // Initial resize.

        // Set stdin in raw mode.
        oldState, err := terminal.MakeRaw(int(os.Stdin.Fd()))
        if err != nil {
                panic(err)
        }
        defer func() { _ = terminal.Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.

        // Copy stdin to the pty and the pty to stdout.
        go func() { _, _ = io.Copy(ptmx, os.Stdin) }()
        _, _ = io.Copy(os.Stdout, ptmx)

        return nil
}

func main() {
        if err := test(); err != nil {
                log.Fatal(err)
        }
}

Documentation

Overview

Package pty provides functions for working with Unix terminals.

Index

• Variables
• func Getsize(t *os.File) (rows, cols int, err error)
• func InheritSize(master, slave *os.File) error
• func Open() (pty, tty *os.File, err error)
• func Setsize(t *os.File, ws *Winsize) error
• func Start(c *exec.Cmd, outputBuf *bytes.Buffer) (pty *os.File, err error)
• type Winsize
  • func GetsizeFull(t *os.File) (size *Winsize, err error)

Variables

var ErrUnsupported = errors.New("unsupported")

ErrUnsupported is returned if a function is not available on the current platform.

Functions

func Getsize

func Getsize(t *os.File) (rows, cols int, err error)

Getsize returns the number of rows (lines) and cols (positions in each line) in terminal t.

func InheritSize

func InheritSize(master, slave *os.File) error

InheritSize applies the terminal size of master to slave. This should be run in a signal handler for syscall.SIGWINCH to automatically resize the slave when the master receives a window size change notification.

func Open

func Open() (pty, tty *os.File, err error)

Opens a pty and its corresponding tty.

func Setsize

func Setsize(t *os.File, ws *Winsize) error

Setsize resizes t to s.

func Start

func Start(c *exec.Cmd, outputBuf *bytes.Buffer) (pty *os.File, err error)

Start assigns a pseudo-terminal tty os.File to c.Stdin, c.Stdout, and c.Stderr, calls c.Start, and returns the File of the tty's corresponding pty.

Types

type Winsize

type Winsize struct {
	Rows uint16 // ws_row: Number of rows (in cells)
	Cols uint16 // ws_col: Number of columns (in cells)
	X    uint16 // ws_xpixel: Width in pixels
	Y    uint16 // ws_ypixel: Height in pixels
}

Winsize describes the terminal size.

func GetsizeFull

func GetsizeFull(t *os.File) (size *Winsize, err error)

GetsizeFull returns the full terminal size description.