A Go application to copy the contents of a source file to a target file

main.go

package main

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

func main() {
	var sourceFile = flag.String(
		"source",
		"source.json",
		"The file to use as a source to copy from",
	)

	var targetFile = flag.String(
		"target",
		"target.json",
		"The file to use as a target to write to",
	)

	flag.Parse()

	fileContents, readErr := ioutil.ReadFile(*sourceFile)

	if readErr != nil {
		fmt.Println("Found an error while reading the source file: " + readErr.Error())
		os.Exit(1)
	}

	writeErr := ioutil.WriteFile(*targetFile, fileContents, 0644)

	if writeErr != nil {
		fmt.Println("Found an error while writing to the target file: " + writeErr.Error())
		os.Exit(1)
	}

	fmt.Println("Copied the contents of " + *sourceFile + " to " + *targetFile)
}