Book Image

Mastering Go - Second Edition

By : Mihalis Tsoukalos
Book Image

Mastering Go - Second Edition

By: Mihalis Tsoukalos

Overview of this book

Often referred to (incorrectly) as Golang, Go is the high-performance systems language of the future. Mastering Go, Second Edition helps you become a productive expert Go programmer, building and improving on the groundbreaking first edition. Mastering Go, Second Edition shows how to put Go to work on real production systems. For programmers who already know the Go language basics, this book provides examples, patterns, and clear explanations to help you deeply understand Go’s capabilities and apply them in your programming work. The book covers the nuances of Go, with in-depth guides on types and structures, packages, concurrency, network programming, compiler design, optimization, and more. Each chapter ends with exercises and resources to fully embed your new knowledge. This second edition includes a completely new chapter on machine learning in Go, guiding you from the foundation statistics techniques through simple regression and clustering to classification, neural networks, and anomaly detection. Other chapters are expanded to cover using Go with Docker and Kubernetes, Git, WebAssembly, JSON, and more. If you take the Go programming language seriously, the second edition of this book is an essential guide on expert techniques.
Table of Contents (20 chapters)
Title Page

User ID and group ID

In this section, you will learn how to find the user ID of the current user, as well as the group IDs to which the current user belongs. Both the user ID and group IDs are positive integers kept in UNIX system files.

The name of the utility is ids.go, and it will be presented in two parts. The first part of the utility follows:

package main 
import ( 
func main() { 
    fmt.Println("User id:", os.Getuid()) 

Finding the user ID of the current user is as simple as calling the os.Getuid() function.

The second part of ids.go is as follows:

    var u *user.User 
    u, _ = user.Current() 
    fmt.Print("Group ids: ") 
    groupIDs, _ := u.GroupIds() 
    for _, i := range groupIDs { 
        fmt.Print(i, " ") 

On the other hand, finding...