Golang : Convert file content into array of bytes

It is a fairly common requirement to read a file content into array of bytes and output those arrays back to a file. In this tutorial, we will explore how to convert file content into array of bytes in Go.

See the example code below :


 package main

 import (

 func main () {
 file, err := os.Open("testdata.txt")

 if err != nil {

 defer file.Close()

 reader := bufio.NewReader(file)
 buffer := bytes.NewBuffer(make([] byte,0))

 var chunk []byte
 var eol bool
 var str_array []string

 for {
 if chunk, eol, err = reader.ReadLine(); err != nil {
 if !eol {
 str_array = append(str_array, buffer.String())

 if err == io.EOF {
 err = nil

 fmt.Println(str_array) // you can redirect the str_array content to a file here instead of println

Reference :

How to generate checksum for file in Go



  See also : Golang : Read binary file into memory

By Adam Ng

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