Book Image

Learning Go Programming

Book Image

Learning Go Programming

Overview of this book

The Go programming language has firmly established itself as a favorite for building complex and scalable system applications. Go offers a direct and practical approach to programming that let programmers write correct and predictable code using concurrency idioms and a full-featured standard library. This is a step-by-step, practical guide full of real world examples to help you get started with Go in no time at all. We start off by understanding the fundamentals of Go, followed by a detailed description of the Go data types, program structures and Maps. After this, you learn how to use Go concurrency idioms to avoid pitfalls and create programs that are exact in expected behavior. Next, you will be familiarized with the tools and libraries that are available in Go for writing and exercising tests, benchmarking, and code coverage. Finally, you will be able to utilize some of the most important features of GO such as, Network Programming and OS integration to build efficient applications. All the concepts are explained in a crisp and concise manner and by the end of this book; you would be able to create highly efficient programs that you can deploy over cloud.
Table of Contents (18 chapters)
Learning Go Programming
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface

Working with files


The os package (https://golang.org/pkg/os/) exposes the os.File type which represents a file handle on the system. The os.File type implements several IO primitives, including the io.Reader and io.Writer interfaces, which allows file content to be processed using the standard streaming IO API.

Creating and opening files

The os.Create function creates a new file with the specified path. If the file already exists, os.Create will overwrite it. The os.Open function, on the other hand, opens an existing file for reading.

The following source snippet opens an existing file and creates a copy of its content using the io.Copy function. One common, and recommended practice to notice is the deferred call to the method Close on the file. This ensures a graceful release of OS resources when the function exits:

func main() { 
   f1, err := os.Open("./file0.go") 
   if err != nil { 
         fmt.Println("Unable to open file:", err) 
         os.Exit(1) 
   } &...