Unix/ls

Task

Write a program that will list everything in the current folder, similar to:

the Unix utility “ls” [1] or
the Windows terminal command “DIR”

The output must be sorted, but printing extended details and producing multi-column output is not required.

Example output

For the list of paths:

/foo/bar
/foo/bar/1
/foo/bar/2
/foo/bar/a
/foo/bar/b

When the program is executed in `/foo`, it should print:

bar

and when the program is executed in `/foo/bar`, it should print:

1
2
a
b

8th

Arturo

<lang arturo>print [dirContent "."]</lang>

AWK

Works with: gawk

"BEGINFILE" is a gawk-extension

syntax: GAWK -f UNIX_LS.AWK * | SORT

BEGINFILE {

   printf("%s\n",FILENAME)
   nextfile

} END {

   exit(0)

} </lang>

Sample commands and output under Windows 8:

REM create folders and files
MKDIR c:\foo\bar
CD /D c:\foo\bar
GAWK "BEGIN{x=\"12ab\";for(i=1;i<=length(x);i++){print(i)>substr(x,i,1)}}"
REM run test
CD /D c:\foo
GAWK -f UNIX_LS.AWK * | SORT
bar
CD /D c:\foo\bar
GAWK -f UNIX_LS.AWK * | SORT
1
2
a
b

Works with: gawk

To replicate 'ls .'

gawk -lreaddir 'BEGIN { FS = "/" } {print $2}' .

Works with: gawk

To replicate 'ls examplefile.txt'

gawk -lfilefuncs -lreaddir 'BEGIN { FS = "/"; stat(ARGV[1], fd); if(fd["type"] == "file") {print ARGV[1]; exit} } { print $2}' examplefile.txt

Clojure

<lang clojure>(def files (sort (filter #(= "." (.getParent %)) (file-seq (clojure.java.io/file ".")))))

(doseq [n files] (println (.getName n)))</lang>

In some implementations, `(directory)` results automatically include subdirectories (e.g. SBCL); some require them to be requested separately (e.g. CLISP). The function below asks for both and then removes any duplicates from the resulting list.

The workhorse is `files-list`, which returns a list of filenames. The `ls` function sorts the resulting list and formats it for output.

<lang lisp>(defun files-list (&optional (path "."))

 (let* ((dir (concatenate 'string path "/"))
        (abs-path (car (directory dir)))
        (file-pattern (concatenate 'string dir "*"))
        (subdir-pattern (concatenate 'string file-pattern "/")))
   (remove-duplicates
      (mapcar (lambda (p) (enough-namestring p abs-path))
              (mapcan #'directory (list file-pattern subdir-pattern)))
      :test #'string-equal)))

(defun ls (&optional (path "."))

 (format t "~{~a~%~}" (sort (files-list path) #'string-lessp)))</lang>

D

<lang d>void main() {

   import std.stdio, std.file, std.path, std.array, std.algorithm;

   foreach (const string path; dirEntries(getcwd, SpanMode.shallow).array.sort)
       path.baseName.writeln;

}</lang>

EchoLisp

No directory in EchoLisp, which is run in a browser window. Instead, "stores" (folders) and keys in stores (file names) are located in local storage. <lang lisp>

ls of stores (kind of folders)

(for-each writeln (list-sort < (local-stores))) →

   AGES    
   NEMESIS    
   info    
   objects.dat    
   reader    
   system    
   user    
   words

ls of "NEMESIS" store

(for-each writeln (local-keys "NEMESIS")) →

   Alan    
   Glory    
   Jonah

</lang>

Elixir

<lang elixir>iex(1)> ls = fn dir -> File.ls!(dir) |> Enum.each(&IO.puts &1) end

Function<6.54118792/1 in :erl_eval.expr/5>

iex(2)> ls.("foo") bar

ok

iex(3)> ls.("foo/bar") 1 2 a b

ok</lang>

Erlang

<lang erlang> 1> Ls = fun(Dir) -> 1> {ok, DirContents} = file:list_dir(Dir), 1> [io:format("~s~n", [X]) || X <- lists:sort(DirContents)] 1> end.

Fun<erl_eval.6.36634728>

2> Ls("foo"). bar [ok] 3> Ls("foo/bar"). 1 2 a b [ok,ok,ok,ok] </lang>

F#

Works with .NET framework 4.

<lang fsharp>let ls = DirectoryInfo(".").EnumerateFileSystemInfos() |> Seq.map (fun i -> i.Name) |> Seq.sort |> Seq.iter (printfn "%s")</lang>

Prior to .NET4 you had to enumerate files and directories separately.

The call to sort is probably redundant, since "sorted by name" seems to be the default in Windows.

Forth

This is much easier without the 'sorted output' requirement: <lang forth>256 buffer: filename-buf

each-filename { xt -- } \ xt-consuming variant

 s" ." open-dir throw { d }
 begin filename-buf 256 d read-dir throw while
   filename-buf swap xt execute
 repeat  d close-dir throw ;

\ immediate variant

each-filename[ s" ." postpone sliteral ]] open-dir throw >r begin filename-buf 256 r@ read-dir throw while filename-buf swap [[ ; immediate compile-only

]each-filename ]] repeat drop r> close-dir throw [[ ; immediate compile-only

ls ( -- ) [: cr type ;] each-filename ;</lang>

Given that requirement, we must first generate a sorted array of filenames:

Library: Forth Foundation Library

<lang forth>: save-string ( c-addr u -- a )

 dup 1+ allocate throw dup >r place r> ;

require ffl/car.fs

sorted-filenames ( -- car )

 0 car-new { a }
 [: swap count rot count compare ;] a car-compare!
 each-filename[ save-string a car-insert-sorted ]each-filename
 a ;

each-sorted-filename ( xt -- )

 sorted-filenames { a }  a car-execute  [: free throw ;] a car-execute  a car-free ;

ls ( -- )

 [: count cr type ;] each-sorted-filename ;

</lang>

Fortran

This is possible only for those Fortran compilers that offer some sort of interface with the operating system's file handling routines. Not standard at all! <lang Fortran> PROGRAM LS !Names the files in the current directory.

     USE DFLIB			!Mysterious library.
     TYPE(FILE$INFO) INFO	!With mysterious content.
     NAMELIST /HIC/INFO	!This enables annotated output.
     INTEGER MARK,L		!Assistants.

     MARK = FILE$FIRST		!Starting state.

Call for the next file.

  10 L = GETFILEINFOQQ("*",INFO,MARK)	!Mystery routine returns the length of the file name.
     IF (MARK.EQ.FILE$ERROR) THEN	!Or possibly, not.
       WRITE (6,*) "Error!",L		!Something went wrong.
       WRITE (6,HIC)			!Reveal INFO, annotated.
       STOP "That wasn't nice."	!Quite.
     ELSE IF (IAND(INFO.PERMIT,FILE$DIR) .EQ. 0) THEN	!Not a directory.
       IF (L.GT.0) WRITE (6,*) INFO.NAME(1:L)	!The object of the exercise!
     END IF				!So much for that entry.
     IF (MARK.NE.FILE$LAST) GO TO 10	!Lastness is discovered after the last file is fingered.
     END	!If FILE$LAST is not reached, "system resources may be lost." </lang>

This relies on the supplied routine GETFILEINFOQQ, which is not at all a standard routine, but it does behave in the same way as is found in many other systems, notably with a file name selection filter, here chosen to be "*" meaning "any file". It supplies successive file names and requires mysterious parameters to keep track of what it is doing. In the installation file C:/Compilers/Furrytran/Compaq Furrytran 6.6a CD/X86/DF/INCLUDE/DFLIB.F90, there is the following segment: <lang Fortran> INTERFACE INTEGER*4 FUNCTION GETFILEINFOQQ(FILES, BUFFER,dwHANDLE) !DEC$ ATTRIBUTES DEFAULT :: GETFILEINFOQQ CHARACTER*(*) FILES STRUCTURE / FILE$INFO / INTEGER*4 CREATION ! Creation time (-1 on FAT) INTEGER*4 LASTWRITE ! Last write to file INTEGER*4 LASTACCESS ! Last access (-1 on FAT) INTEGER*4 LENGTH ! Length of file INTEGER*2 PERMIT ! File access mode CHARACTER*255 NAME ! File name END STRUCTURE RECORD / FILE$INFO / BUFFER INTEGER*4 dwHANDLE END FUNCTION

     END INTERFACE</lang>

Getting this to work was quite annoying. It turned out that the irritating "files" . and .. are deemed a directory (via the bit in INFO.PERMIT matching that of FILE$DIR = 16) and so can be skipped along with proper subdirectories, but the "PERMIT" value of -1 returned for the FILE$LAST state also matches, though its (non-existent) file name length is given as zero. Thus, if one skips directories filter-style by IF ... GO TO 10, in such a case the end will never be seen. Further, although Fortran syntax allows INFO.PERMIT .AND. FILE$DIR the bit values of logical variables are strange. Instead, what is needed is IAND(INFO.PERMIT,FILE$DIR)

Further vexation was due to the compiler's "help" system giving PERMIT as a 32-bit integer in its example. Copying the declaration to give a type name not involving a dollar symbol foundered because the type checking done by the compiler for the parameters of the function is based not on the contents of the type matching, but on the name of the type matching. So, one is stuck with the $. In a mood for retaliation, some special tests were made, involving a pause for input after each name was revealed. Removing the file just named before responding to the request for input did not prevent the next file from being named, nor (in another run) did removing the file next to be named: although it was gone, it was still named in the next step as if it were still there, and this worked even if INFO.NAME were scrubbed each time as well. Evidently, there could arise transient problems when using this scheme in a file system undergoing turbulence.

As for the ordering of results, on this Windows XP system, the file names came out ordered so there is no need to mess about with a storage area to sort the names in.

FunL

<lang funl>import io.File

for f <- sort( list(File( "." ).list()).filterNot(s -> s.startsWith(".")) )

   println( f )</lang>

Output:

The above script has been placed in a file called ls.lf which has been placed in the home directory.

$ sudo mkdir -p /foo/bar
$ cd /foo/bar
$ sudo touch 1 2 a b
$ cd ..
$ funl ~/ls
bar
$ cd bar
$ funl ~/ls
1
2
a
b
$

Gambas

<lang gambas>Public Sub Main() Dim sDir As String[] = Dir(User.Home &/ "test").Sort()

Print sDir.Join(gb.NewLine)

End</lang> Output:

a.txt
b.txt
c.txt
d.txt
e.txt

Go

<lang go>package main

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

func main() { f, err := os.Open(".") if err != nil { log.Fatal(err) } files, err := f.Readdirnames(0) f.Close() if err != nil { log.Fatal(err) } sort.Strings(files) for _, n := range files { fmt.Println(n) } }</lang>

Haskell

Works with: GHC version 7.8.3

<lang haskell>import Control.Monad import Data.List import System.Directory

dontStartWith = flip $ (/=) . head

main = do

 files <- getDirectoryContents "."
 mapM_ putStrLn $ sort $ filter (dontStartWith '.') files</lang>

J

See the dir.ijs script for a full description of the interface for dir: <lang J> dir NB. includes properties

  >1 1 dir   NB. plain filename as per task</lang>

Java

Works with: Java version 11

<lang java> package rosetta;

import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path;

public class UnixLS {

public static void main(String[] args) throws IOException { Files.list(Path.of("")).sorted().forEach(System.out::println); } } </lang>

The challenge does not state that the files must be sorted in case-insensitive order, and the majority of solutions in other languages do not bother with same. The above can be expanded to sort case-insensitively by mapping Path to String and using the predefined String Comparator: <lang java> Files.list(Path.of("")).map(Path::toString).sorted(String.CASE_INSENSITIVE_ORDER).forEach(System.out::println); </lang>

JavaScript

Works with: Node.js version 4.3.2+

<lang javascript>const fs = require('fs'); fs.readdir('.', (err, names) => names.sort().map( name => console.log(name) ));</lang>

Jsish

Jsi provides a File module with a glob method.

# help File.glob
File.glob(pattern:regexp|string|null='*', options:function|object|null=void):array
Return list of files in dir with optional pattern match.
With no arguments (or null) returns all files/directories in current directory.
The first argument can be a pattern (either a glob or regexp) of the files to return.
When the second argument is a function, it is called with each path, and filter on false.
Otherwise second argument must be a set of options.

To emulate ls, sorted, one entry per line:

Julia

<lang julia># v0.6.0

for e in readdir() # Current directory

   println(e)

end

Same for...

readdir("~") # Read home directory readdir("~/documents")</lang>

Kotlin

<lang scala>// Version 1.2.41

import java.io.File

fun ls(directory: String) {

   val d = File(directory)
   if (!d.isDirectory) {
       println("$directory is not a directory")
       return
   }
   d.listFiles().map { it.name }
                .sortedBy { it.toLowerCase() }  // case insensitive
                .forEach { println(it) }

}

fun main(args: Array<String>) {

   ls(".")  // list files in current directory, say

}</lang>

LiveCode

<lang LiveCode>set the defaultFolder to "/foo" put the folders & the files set the defaultFolder to "/foo/bar" put the folders & the files</lang>

Lua

Using LuaFileSystem - available in LuaRocks, ULua, major Linux distro repos, etc, etc. <lang Lua>require("lfs") for file in lfs.dir(".") do print(file) end</lang>

Mathematica

<lang Mathematica>Column[FileNames[]]</lang>

Nanoquery

<lang nanoquery>mport Nanoquery.IO import sort

fnames = sort(new(File).listDir("."))

for i in range(0, len(fnames) - 1)

   println fnames[i]

end</lang>

Output:

.\nanoquery-2.3_1866                                                                                               .\notes.txt                                                                                                        .\nq.bat                                                                                                           .\nq.vim                                                                                                           .\rosetta-code

Nim

<lang Nim> from algorithm import sorted from os import walkPattern from sequtils import toSeq

for path in toSeq(walkPattern("*")).sorted:

 echo path

</lang>

Objeck

<lang objeck> class Test {

 function : Main(args : String[]) ~ Nil {
   file_names := System.IO.File.Directory->List(".");
   each(i : file_names) {
     file_name := file_names[i];
     if(System.IO.File.Directory->Exists(file_name)) {
       file_name += '/';
     };
     file_name->PrintLine();
   };
 }

} </lang>

OCaml

<lang ocaml>let () =

 Array.iter print_endline (
   Sys.readdir Sys.argv.(1) )</lang>

Output:

$ cd /foo/bar
$ ocaml ls.ml
1
2
a
b

PARI/GP

GP doesn't have this capability so we can either use the shell or PARI. For the latter see C; for the former: <lang parigp>system("dir/b/on")</lang> in DOS/Windows or <lang parigp>system("ls")</lang> in *nix.

Pascal

This is the example in the Turbo Pascal 4 manual. With Turbo Pascal and old-style DOS file names, all file names come out in capitals, further, names not fitting into the "8.3" style (of up to eight characters followed by an extension of up to three characters) are presented with ad-hoc names fitting that style, so for example, Tab2Comma.exe comes out as TAB2CO~1.EXE. The same source file compiles unchanged via the Free Pascal compiler, whereupon long file names appear with capitals and lower-case letters rather than all-capitals.

When tested via Windows XP, the names came out in sorted order (ignoring case) however in earlier systems the files would be presented in entry order. That is, if files a, c, b were saved, they would be named in that order. Then, if file c were deleted and then a file named x were added, they would be named in the order a, x, b. In this case, a scheme for saving an unknown number of names (of unknown length) would be needed so that they could be sorted. Perhaps some linked-list with an insertionsort for each added name... <lang Pascal> Program ls; {To list the names of all files/directories in the current directory.}

Uses DOS;
var DirInfo: SearchRec;	{Predefined. See page 403 of the Turbo Pascal 4 manual.}
BEGIN
 FindFirst('*.*',AnyFile,DirInfo);	{AnyFile means any file name OR directory name.}
 While DOSerror = 0 do			{Result of FindFirst/Next not being a function, damnit.}
  begin
   WriteLn(DirInfo.Name);
   FindNext(DirInfo);
  end;
END.

</lang>

Perl

<lang perl>opendir my $handle, '.' or die "Couldnt open current directory: $!"; while (readdir $handle) {

   print "$_\n";

} closedir $handle;</lang>

Alternatively, using glob: <lang perl>print "$_\n" for glob '*';</lang>

<lang perl>print "$_\n" for glob '* .*'; # If you want to include dot files</lang>

Perl 6

There is a dir builtin command which returns a list of IO::Path objects. We stringify them all with a hyperoperator before sorting the strings.

Phix

Output:

{{".", "d", 0,2017,4,3,21,0,7},
 {"..", "d", 0,2017,4,3,21,0,7},
 {".hg", "d", 0,2017,3,27,13,53'5',38'&'},
 {".hgignore", "a", 15330,2017,3,27,13,29,21},
 {"alice_oz.txt", "a", 336926,2017,3,15,19,12,24},
 {"asm", "d", 0,2017,4,2,20,33'!',39'''},
...etc

PHP

This will output all the filenames in the current directory.

<lang php> <?php foreach(scandir('.') as $fileName){

   echo $fileName."\n";

} </lang>

PicoLisp

<lang PicoLisp>(for F (sort (dir))

  (prinl F) )</lang>

Pike

<lang Pike>foreach(get_dir(), string file)

   write(file +"\n");</lang>

PowerShell

<lang PowerShell># Prints Name, Length, Mode, and LastWriteTime Get-ChildItem | Sort-Object Name | Write-Output

Prints only the name of each file in the directory

Get-ChildItem | Sort-Object Name | ForEach-Object Name | Write-Output</lang>

Python

<lang python>>>> import os >>> print('\n'.join(sorted(os.listdir('.')))) DLLs Doc LICENSE.txt Lib NEWS.txt README.txt Scripts Tools include libs python.exe pythonw.exe tcl >>> </lang>

R

<lang rsplus> cat(paste(list.files(), collapse = "\n"), "\n") cat(paste(list.files("bar"), collapse = "\n"), "\n") </lang>

Output:

bar 
1
2
a
b

Racket

Ooh... warning... if you run the test module (either with DrRacket with the test module automatically running, or with raco test ls.rkt, then the example directory tree is built but not torn down.

<lang racket>#lang racket/base

Racket's `directory-list' produces a sorted list of files

(define (ls) (for-each displayln (directory-list)))

Code to run when this file is running directly

(module+ main

 (ls))

(module+ test

 (require tests/eli-tester racket/port racket/file)
 (define (make-directory-tree)
   (make-directory* "foo/bar")
   (for ([f '("1" "2" "a" "b")])
     (with-output-to-file (format "foo/bar/~a"f) #:exists 'replace newline)))
 (make-directory-tree)
 (define (ls/str dir)
   (parameterize ([current-directory dir]) (with-output-to-string ls)))
 (test (ls/str "foo") => "bar\n"
       (ls/str "foo/bar") => "1\n2\na\nb\n"))</lang>

Both tests pass.

REXX

The following program works under Windows and used the Windows DIR command to list a bare-bones sorted list. <lang rexx>/*REXX program lists contents of current folder (ala mode UNIX's LS). */ 'DIR /b /oN' /*use Windows DIR: sorts & lists.*/

                                      /*stick a fork in it, we're done.*/</lang>

Notes on the options used for the DIR command:

b is for bare format (no heading information or summary).
o is for order, and it orders (sorts) by file Name.

Ruby

<lang ruby> Dir.foreach("./"){|n| puts n} </lang> This will output all files including hidden ones e.g. '.' and '..'.

Run BASIC

<lang Runbasic>files #f, DefaultDir$ + "\*.*" ' RunBasic Default directory.. Can be any directroy print "rowcount: ";#f ROWCOUNT() ' how many rows in directory

f DATEFORMAT("mm/dd/yy") 'set format of file date or not
f TIMEFORMAT("hh:mm:ss") 'set format of file time or not

count = #f rowcount() for i = 1 to count ' loop thru the row count print "info: ";#f nextfile$() ' file info print "name: ";#f NAME$() ' Name of file print "size: ";#f SIZE() ' size print "date: ";#f DATE$() ' date print "time: ";#f TIME$() ' time print "isdir: ";#f ISDIR() ' 1 = is a directory next</lang> This will output RunBasics Default Directory.. It can be any directory

rowcount: 30
info: antiGram1.bas,1743,08/02/16,08:34:50,
name: antiGram1.bas
size: 1743
date: 08/02/16
time: 08:34:50
isdir: 0
info: avionics.db,0,05/09/16,09:02:01,
name: avionics.db
size: 0
date: 05/09/16
time: 09:02:01
isdir: 0
...

Rust

<lang rust>use std::{env, fmt, fs, process}; use std::io::{self, Write}; use std::path::Path;

fn main() {

   let cur = env::current_dir().unwrap_or_else(|e| exit_err(e, 1));
   let arg = env::args().nth(1);
   print_files(arg.as_ref().map_or(cur.as_path(), |p| Path::new(p)))
       .unwrap_or_else(|e| exit_err(e, 2));

}

[inline]

fn print_files(path: &Path) -> io::Result<()> {

   for x in try!(fs::read_dir(path)) {
       println!("{}", try!(x).file_name().to_string_lossy());
   }
   Ok(())

}

[inline]

fn exit_err<T>(msg: T, code: i32) -> ! where T: fmt::Display {

   writeln!(&mut io::stderr(), "{}", msg).expect("Could not write to stderr");
   process::exit(code)

}</lang>

Output:

$ mkdir -p foo/bar
$ ./unix_ls
foo
unix_ls
$ cd foo/bar
$ touch a b 1 2
$ cd ../..
$ ./unix_ls foo
bar
$ ./unix_ls foo/bar
1
2
a
b

S-lang

<lang S-lang>variable d = listdir(getcwd()), p; foreach p (array_sort(d))

 () = printf("%s\n", d[p] );</lang>

Scala

Output:

scala> new java.io.File("/").listFiles.sorted.foreach(println)
/bin
/boot
/core
/dev
/etc
/home
/lib
/lib64
/local
/lost+found
/media
/mnt
/opt
/proc
/root
/run
/sbin
/selinux
/srv
/sys
/tmp
/user
/usr
/var

Seed7

<lang seed7>$ include "seed7_05.s7i";

 include "osfiles.s7i";

const proc: main is func

 local
   var string: name is "";
 begin
   for name range readDir(".") do
      writeln(name);
   end for;
 end func;</lang>

Sidef

Explicit, by opening the current working directory: <lang ruby>var content = []; Dir.cwd.open.each { |file|

   file ~~ < . .. > && next;
   content.append(file);

}

content.sort.each { |file|

   say file;

}</lang>

Implicit, by using the String.glob method: <lang ruby>'*'.glob.each { |file|

   say file;

}</lang>

Standard ML

<lang sml>OS.Process.system "ls -a" </lang> Doing it all by yourself: <lang sml> local (* make a sort function *)

 val rec insert = fn s :string =>fn [] => [s]

| ll as h::t => if s<=h then s::ll else h::insert s t; in

 val rec sort = fn [] => [] | h::t => insert h (sort t)

end;

open Posix.FileSys ; val istream = opendir "." ; val ll = ref [readdir istream] ; while ( isSome (hd (!ll)) ) do ( ll:=readdir istream :: !ll ); val result = List.map valOf (tl (!ll)); closedir istream ;

sort result; </lang>

Stata

Stata has a builtin dir command (or equivalently ls).

<lang stata>. dir *.dta

  6.3k   6/12/17 14:26  auto.dta
  2.3k   8/10/17  7:34  titanium.dta
  6.0k   8/12/17  9:28  trend.dta</lang>

Tcl

<lang tcl>puts [join [lsort [glob -nocomplain *]] "\n"]</lang>

Ursa

<lang ursa>decl file f decl string<> fnames set fnames (sort (f.listdir "."))

for (decl int i) (< i (size fnames)) (inc i)

       out fnames endl console

end for</lang>
zkl
<lang zkl>File.glob("*").sort()</lang> Lists all files and directories in the current directory. If you only want a list of files: <lang zkl>File.glob("*",0x8).sort()</lang>

Output:
L("README","superball","testThemAll.log","zkl.exe","zkl_tests.zip","zkl_vm_src.zip")
The glob method uses Unix shell wild cards.
The globular method recurses down through the directories. It can send results to objects, functions, methods, threads, etc, etc. To get a sorted list of all the directories under the "Src" directory: <lang zkl>File.globular("Src",*,True,0x10,List).sort().concat("\n")</lang>

Output:
Src/Compiler/ Src/Misc/ Src/Test/ Src/Time/ Src/Utils/ Src/ZenKinetic/ Src/ZenKinetic/Frame_O_Matic/ Src/ZenKinetic/GBalls/ Src/ZenKinetic/Twist and Draw/ Src/ZenKinetic/ZEd