sh.go

package main

import (
	"bytes"
	"fmt"
	"log"
	"os/exec"
	"strings"
)

type Session struct {
	Stdout string
}

func (s *Session) Command(name string, args ...string) *Session {
	cmd := exec.Command(name, args...)
	cmd.Stdin = strings.NewReader(s.Stdout)
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		log.Fatal(err)
	}
	s.Stdin = out.String()
	return s
}

func (s *Session) Exec() {
	fmt.Printf(s.Stdout)
}

func main() {
	s := Session{}
	s.Command("ls", "-1").Command("grep", ".go").Exec()
}

$ go run sh.go
main.go
shell.go
sh.go
torrent-client.go