Golang : How to pipe input data to executing child process?

Problem :

Your program is executing a child process via os/exec and you want to pipe input data to the executing process.

Solution :

Use the StdinPipe() method and issue a .Write([]byte(your data)) to input data to the executing child process.

For example :

 package main

 import (
  "fmt"
  "os/exec"
 )

 func main() {
  cmd := exec.Command("cat")

  stdin, err := cmd.StdinPipe()

  stdin.Write([]byte("Hello World!")) // <------ here
  stdin.Close()

  if err != nil {
 panic(err)
  }

  data, err := cmd.Output()

  if err != nil {
 panic(err)
  }

  for k, v := range data {
 fmt.Printf("key :  %v, value :  %v \n", k, string(v))
  }
 }