List directory in Go

Question

I ve been trying to figure out how to simply list the files and folders in a single directory in Go   I ve found filepath Walk  but it goes into sub-directories automatically  which I don t want   All of my other searches haven t turned anything better up     I m sure that this functionality exists  but it s been really hard to find   Let me know if anyone knows where I should look   Thanks

User · Accepted Answer

You can try using the ReadDir function in the io/ioutil package. Per the docs:

ReadDir reads the directory named by dirname and returns a list of sorted directory entries.

The resulting slice contains os.FileInfo types, which provide the methods listed here. Here is a basic example that lists the name of everything in the current directory (folders are included but not specially marked - you can check if an item is a folder by using the IsDir() method):

package main

import (
    "fmt"
    "io/ioutil"
     "log"
)

func main() {
    files, err := ioutil.ReadDir("./")
    if err != nil {
        log.Fatal(err)
    }
 
    for _, f := range files {
            fmt.Println(f.Name())
    }
}

User · Answer

We can get a list of files inside a folder on the file system using various golang standard library functions    filepath Walk ioutil ReadDir os File Readdir    package main  import        fmt       io ioutil       log       os       path filepath     func main         var           root  string         files   string         err   error            root      home manigandan golang samples         filepath Walk     files  err   FilePathWalkDir root      if err    nil           panic err               ioutil ReadDir     files  err   IOReadDir root      if err    nil           panic err              os File Readdir     files  err   OSReadDir root      if err    nil           panic err             for    file    range files           fmt Println file             Using filepath Walk      The path filepath package provides a handy way to scan all the files   in a directory  it will automatically scan each sub-directories in the   directory    func FilePathWalkDir root string     string  error        var files   string     err    filepath Walk root  func path string  info os FileInfo  err error  error           if  info IsDir                 files   append files  path                    return nil            return files  err      Using ioutil ReadDir      ioutil ReadDir reads the directory named by dirname and returns a   list of directory entries sorted by filename    func IOReadDir root string     string  error        var files   string     fileInfo  err    ioutil ReadDir root      if err    nil           return files  err            for    file    range fileInfo           files   append files  file Name              return files  nil      Using os File Readdir      Readdir reads the contents of the directory associated with file and   returns a slice of up to n FileInfo values  as would be returned by   Lstat  in directory order  Subsequent calls on the same file will   yield further FileInfos    func OSReadDir root string     string  error        var files   string     f  err    os Open root      if err    nil           return files  err           fileInfo  err    f Readdir -1      f Close       if err    nil           return files  err            for    file    range fileInfo           files   append files  file Name              return files  nil     Benchmark results     Get more details on this Blog Post

User · Answer

Even simpler  use path filepath   package main      import        fmt       log       path filepath     func main         files  err    filepath Glob          if err    nil           log Fatal err            fmt Println files     contains a list of all files in the current directory

User · Answer

Starting with Go 1 16  you can use the os ReadDir function   func ReadDir name string     DirEntry  error    It reads a given directory and returns a DirEntry slice that contains the directory entries sorted by filename  It s an optimistic function  so that  when an error occurs while reading the directory entries  it tries to return you a slice with the filenames up to the point before the error  package main  import        quot fmt quot       quot log quot       quot os quot     func main         files  err    os ReadDir  quot   quot       if err    nil           log Fatal err             for    file    range files           fmt Println file Name              Background Go 1 16  Q1 2021  will propose  with CL 243908 and CL 243914   the ReadDir function  based on the FS interface     An FS provides access to a hierarchical file system        The FS interface is the minimum implementation required of the file system     A file system may implement additional interfaces     such as fsutil ReadFileFS  to provide additional or optimized functionality     See io fsutil for details  type FS interface          Open opens the named file                When Open returns an error  it should be of type  PathError        with the Op field set to  quot open quot   the Path field set to name         and the Err field describing the problem                Open should reject attempts to open names that do not satisfy        ValidPath name   returning a  PathError with Err set to        ErrInvalid or ErrNotExist      Open name string   File  error     That allows for  quot os  add ReadDir method for lightweight directory reading quot   See commit a4ede9f     ReadDir reads the contents of the directory associated with the file f    and returns a slice of DirEntry values in directory order     Subsequent calls on the same file will yield later DirEntry records in the directory        If n  gt  0  ReadDir returns at most n DirEntry records     In this case  if ReadDir returns an empty slice  it will return an error explaining why     At the end of a directory  the error is io EOF        If n  lt   0  ReadDir returns all the DirEntry records remaining in the directory     When it succeeds  it returns a nil error  not io EOF   func  f  File  ReadDir n int     DirEntry  error       A DirEntry is an entry read from a directory  using the ReadDir method   type DirEntry interface          Name returns the name of the file  or subdirectory  described by the entry         This name is only the final element of the path  not the entire path         For example  Name would return  quot hello go quot  not  quot  home gopher hello go quot       Name   string             IsDir reports whether the entry describes a subdirectory      IsDir   bool             Type returns the type bits for the entry         The type bits are a subset of the usual FileMode bits  those returned by the FileMode Type method      Type   os FileMode             Info returns the FileInfo for the file or subdirectory described by the entry         The returned FileInfo may be from the time of the original directory read        or from the time of the call to Info  If the file has been removed or renamed        since the directory read  Info may return an error satisfying errors Is err  ErrNotExist          If the entry denotes a symbolic link  Info reports the information about the link itself         not the link s target      Info    FileInfo  error     src os os test go testReadDir   illustrates its usage      file  err    Open dir      if err    nil           t Fatalf  quot open  q failed   v quot   dir  err            defer file Close       s  err2    file ReadDir -1      if err2    nil           t Fatalf  quot ReadDir  q failed   v quot   dir  err2          Ben Hoyt points out in the comments to Go 1 16 os ReadDir   os ReadDir path string     os DirEntry  error   which you ll be able to call directly without the Open dance  So you can probably shorten this to just os ReadDir  as that s the concrete function most people will call   See commit 3d913a9  Dec  2020    os  add ReadFile  WriteFile  CreateTemp  was TempFile   MkdirTemp  was TempDir  from io ioutil io ioutil was a poorly defined collection of helpers  Proposal  40025 moved out the generic I O helpers to io  This CL for proposal  42026 moves the OS-specific helpers to os  making the entire io ioutil package deprecated    os ReadDir returns   DirEntry  in contrast to ioutil ReadDir s   FileInfo   Providing a helper that returns   DirEntry is one of the primary motivations for this change

User · Answer

ioutil ReadDir is a good find  but if you click and look at the source you see that it calls the method Readdir of os File   If you are okay with the directory order and don t need the list sorted  then this Readdir method is all you need

User · Answer

From your description  what you probably want is os Readdirnames   func  f  File  Readdirnames n int   names   string  err error  Readdirnames reads the contents of the directory associated with file and returns a slice of up to n names of files in the directory  in directory order  Subsequent calls on the same file will yield further names      If n  lt   0  Readdirnames returns all the names from the directory in a single slice   Snippet  file  err    os Open path  if err    nil       return err   defer file Close   names  err    file Readdirnames 0  if err    nil       return err   fmt Println names   Credit to SquattingSlavInTracksuit s comment  I d have suggested promoting their comment to an answer if I could

[go] List directory in Go

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