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) (pty *os.File, err error)
• func StartWithSize(c *exec.Cmd, sz *Winsize) (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) (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.

func StartWithSize

func StartWithSize(c *exec.Cmd, sz *Winsize) (pty *os.File, err error)

StartWithSize 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.

This will resize the pty to the specified size before starting the command

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.