How to List the Contents of a Directory in Golang

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To list the content of a directory in Go, you can use the “os.ReadDir()”, “filepath.Walk()”, or “os.File.Readdir()” functions.

Method 1: Using the os.ReadDir() function

The ReadDir() function reads the named directory, returning all its directory entries sorted by filename.

Syntax

func ReadDir(name string) ([]DirEntry, error)

Example

package main

import (
  "fmt"
  "os"
)

func main() {
 dirPath := "../" // The directory you want to list

 // Read the contents of the directory
 entries, err := os.ReadDir(dirPath)
 if err != nil {
   fmt.Println("Error reading the directory:", err)
   return
 }

 // Iterate through the directory entries and print their names
 for _, entry := range entries {
   fmt.Println(entry.Name())
 }
}

Output

.DS_Store
env
environment.yml
myenv
new_file.csv
pyvenv.cfg

In this example, we used the os.ReadDir() function to read the contents of a directory (in this case, the current directory represented by “.”). We iterate through the entries and print their names if there are no errors.

Method 2: Using the filepath.Walk() function

The filepath.Walk() is a handy function in Go that can traverse a file tree.

Syntax

func Walk(root string, walkFn WalkFunc) error

Example

package main

import (
  "fmt"
  "os"
  "path/filepath"
)

func visit(files *[]string) filepath.WalkFunc {
  return func(path string, info os.FileInfo, err error) error {
    if err != nil {
      fmt.Println(err)
      return nil
    }
    *files = append(*files, path)
    return nil
  }
}

func main() {
  var files []string

  root := "." // Start at current directory
  err := filepath.Walk(root, visit(&files))
  if err != nil {
    panic(err)
  }

  for _, file := range files {
    fmt.Println(file)
  }
}

Output

Using the filepath.Walk() function

Method 3: Using the os.file.Readdir() function

In Go, you can list all files in a directory using the “os.File.Readdir()” function.

Syntax

func (f *File) Readdir(n int) ([]FileInfo, error)

Example

package main

import (
  "fmt"
  "log"
  "os"
)

func main() {
  dir, err := os.Open(".") // open current directory
  if err != nil {
    log.Fatal(err)
  }
  defer dir.Close()

  fileList, err := dir.Readdir(-1) // -1 means return all the FileInfos
  if err != nil {
    log.Fatal(err)
  }

 for _, file := range fileList {
 fmt.Println(file.Name())
 }
}

Output

app.js
app.cs
Pro.R
share
app.cpp

That’s it.

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