Golang : Check if os.Stdin input data is piped or from terminal

There are times we need to write a program that need to behave in one way according to input from pipe and in another way according to input from terminal ( such as keyboard).

In this tutorial, we will learn how to determine the type of inputs... if it is pipe data or from terminal. The codes below will use data from os.Stdin.Stat() function to determine if the incoming data from terminal or pipe.

 package main

 import (
 "fmt"
 "io/ioutil"
 "os"
 "bufio"
 )

 func main() {
 fi, _ := os.Stdin.Stat() // get the FileInfo struct describing the standard input.

 if (fi.Mode() & os.ModeCharDevice) == 0 {
 fmt.Println("data is from pipe")
 // do things for data from pipe

 bytes, _ := ioutil.ReadAll(os.Stdin)
 str := string(bytes)
 fmt.Println(str)

 } else {
 fmt.Println("data is from terminal")
 // do things from data from terminal

 ConsoleReader := bufio.NewReader(os.Stdin)
 fmt.Println("Enter your name : ")

 input, err := ConsoleReader.ReadString('\n')

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 fmt.Println("Your name is : ",input)

 }

 }

Sample output :

>echo "good morning" | ./checkinput

data is from pipe

good morning

> ./checkinput

data is from terminal

Enter your name :

Boo

Your name is : Boo

Reference :

Golang read from os.Stdin

http://golang.org/pkg/os/#FileMode