Attach and send keys

// Command quickstart runs a command in tmux and prints what it showed.
package main

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"

	"github.com/libtmux/libtmux-go/tmux"
)

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

func run(ctx context.Context) (err error) {
	// A private server: a socket and an empty config of its own, so this
	// neither touches nor is changed by a tmux you already use.
	server, err := tmux.NewServer(tmux.ServerOptions{
		SocketName: "libtmux-quickstart",
		ConfigFile: os.DevNull,
	})
	if err != nil {
		return fmt.Errorf("configure tmux: %w", err)
	}
	session, err := server.NewSession(ctx, tmux.NewSessionRequest{Name: "demo"})
	if err != nil {
		return fmt.Errorf("create session: %w", err)
	}
	// Cleanup runs even when ctx is the reason the program is leaving.
	defer func() {
		err = errors.Join(err, server.Kill(context.WithoutCancel(ctx)))
	}()

	// The command runs in a window of its own, with a terminal.
	result, err := session.Run(ctx, "echo hello from tmux", tmux.RunOptions{})
	if err != nil {
		return fmt.Errorf("run command: %w", err)
	}
	for _, line := range result.Lines {
		fmt.Println(line)
	}
	fmt.Println("exit status:", result.Status)
	return nil
}