1.10 read.wirte from stdin stdout the child process

// 主进程读取子进程执行的结果

package main

import (
	"fmt"
	"os/exec"
	"runtime"
)

func main() {

	var cmd string

	if runtime.GOOS == "windows" {
		cmd = "dir"
	} else {
		cmd = "ls"
	}

	proc := exec.Command(cmd)

	// Output will run the process
	// terminates and returns the standard
	// output in a byte slice.
	buff, err := proc.Output()

	if err != nil {
		panic(err)
	}

	// The output of child
	// process in form
	// of byte slice
	// printed as string
	fmt.Println(string(buff))

}

/*
b.go
go_web

*/

stdout

// 输出到标准输出
package main

import (
	"bytes"
	"fmt"
	"os/exec"
	"runtime"
)

func main() {

	var cmd string

	if runtime.GOOS == "windows" {
		cmd = "dir"
	} else {
		cmd = "ls"
	}

	proc := exec.Command(cmd)

	buf := bytes.NewBuffer([]byte{})

	// The buffer which implements
	// io.Writer interface is assigned to
	// Stdout of the process
	proc.Stdout = buf

	// To avoid race conditions
	// in this example. We wait till
	// the process exit.
	proc.Run()

	// The process writes the output to
	// to buffer and we use the bytes
	// to print the output.
	fmt.Println(string(buf.Bytes()))

}

/*
b.go
go_web
*/

标准输入到标准输出

package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	sc := bufio.NewScanner(os.Stdin)

	for sc.Scan() {
		fmt.Println(sc.Text())
	}
}

/*
hhhh
hhhh
jjjj
jjjj
kklkln,k
kklkln,k

*/

package main

import (
	"bufio"
	"fmt"
	"io"
	"os/exec"
	"time"
)

func main() {
	cmd := []string{"go", "run", "sample.go"}

	// The command line tool
	// "ping" is executed for
	// 2 seconds
	proc := exec.Command(cmd[0], cmd[1], cmd[2])

	// The process input is obtained
	// in form of io.WriteCloser. The underlying
	// implementation use the os.Pipe
	stdin, _ := proc.StdinPipe()
	defer stdin.Close()

	// For debugging purposes we watch the
	// output of the executed process
	stdout, _ := proc.StdoutPipe()
	defer stdout.Close()

	go func() {
		s := bufio.NewScanner(stdout)
		for s.Scan() {
			fmt.Println("Program says:" + s.Text())
		}
	}()

	// Start the process
	proc.Start()

	// Now the the following lines
	// are written to child
	// process standard input
	fmt.Println("Writing input")
	io.WriteString(stdin, "Hello\n")
	io.WriteString(stdin, "Golang\n")
	io.WriteString(stdin, "is awesome\n")

	time.Sleep(time.Second * 2)

	proc.Process.Kill()

}