Helper command: returns input from command line OR pipe --- but not both

read.go

package main

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strings"
	"time"
)

/*--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--*/

func main() {
	if len(getArgs()) != 0 && len(getPipe()) != 0 {
		log.Fatal("Both arguments and pipe used. Choose one.")
	} // You cannot have both command-line and piped input
	fmt.Print(getArgs())
	fmt.Print(getPipe())
} // Empty input produces empty output

/*--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--*/

func getArgs() string { // Read command-line parameters
	i := strings.Join(os.Args[1:], " ")
	if len(i) == 0 {
		return ""
	}
	return i
}

func getPipe() string { // Read piped input
	input := make(chan string, 1)
	go readInput(input)
	select {
	case <-time.After(5 * time.Millisecond): // Timeout length
		return ""
	case i := <-input:
		return i
	}
}

/*--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--/\/--*/

func readInput(input chan string) { // Helper function for getPipe()

	scanner := bufio.NewScanner(os.Stdin)
	if scanner.Scan() {
		pipe := scanner.Text()
		input <- pipe
	}
}