Golang : Get all local users and print out their home directory, description and group id

In this short tutorial, we will explore how to get a list of users from the local machine and iterate each one of them to find out their home directory, group ID and description. The code is pretty much self-explanatory and please take note that the code can only be executed on Linux/Unix machine as it will parse the /etc/passwd file to get the users list.

For Windows machine, please see https://www.nextofwindows.com/the-net-command-line-to-list-local-users-and-groups. You can dump out the net users output to a text file first and then parse the text file to build the users list from there.

Here you go!

 package main

 import (
 "bufio"
 "fmt"
 "io"
 "os"
 "os/user"
 "strings"
 )

 var Users []string

 func main() {

 // this is for Linux/Unix machines
 // for Windows
 // see https://www.nextofwindows.com/the-net-command-line-to-list-local-users-and-groups
 file, err := os.Open("/etc/passwd")

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 defer file.Close()

 reader := bufio.NewReader(file)

 for {
 line, err := reader.ReadString('\n')

 // skip all line starting with #
 if equal := strings.Index(line, "#"); equal < 0 {
 // get the username and description
 lineSlice := strings.FieldsFunc(line, func(divide rune) bool {
 return divide == ':' // we divide at colon
 })

 if len(lineSlice) > 0 {
 Users = append(Users, lineSlice[0])
 }

 }

 if err == io.EOF {
 break
 }
 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 }

 // now we have a list of users
 // iterate(cycle) each of them to
 // print out HomeDir, GroupID, description, etc

 for _, name := range Users {

 usr, err := user.Lookup(name)
 if err != nil {
 panic(err)
 }

 // see https://golang.org/pkg/os/user/#User
 fmt.Printf("username:%s\n", usr.Username)
 fmt.Printf("homedir:%s\n", usr.HomeDir)
 fmt.Printf("groupID:%s\n", usr.Gid)
 fmt.Printf("DisplayName:%s\n", usr.Name)
 fmt.Println("*********************************")

 }

 }

Hope this helps and happy coding!

References:

https://www.socketloop.com/tutorials/golang-how-to-get-a-user-home-directory-path#comment-3195013804

https://www.socketloop.com/references/golang-bytes-fieldsfunc-function-example

https://www.socketloop.com/tutorials/golang-skip-or-discard-items-of-non-interest-when-iterating-example

https://golang.org/pkg/strings/#FieldsFunc