View source for Walk a directory/Recursively

{{task|File System Operations}}
[[Category:Recursion]]

;Task:
Walk a given directory ''tree'' and print files matching a given pattern.


'''Note:''' This task is for recursive methods. &nbsp; These tasks should read an entire directory tree, not a ''single directory''.  


'''Note:''' Please be careful when running any code examples found here.


;Related task:
* &nbsp; [[Walk a directory/Non-recursively]] &nbsp; (read a ''single directory''). 
<br><br>

=={{header|11l}}==
{{trans|Nim}}

<syntaxhighlight lang="11l">L(filename) fs:walk_dir(‘/’)
   I re:‘.*\.mp3’.match(filename)
      print(filename)</syntaxhighlight>

=={{header|8th}}==
<syntaxhighlight lang="forth">
"*.c" f:rglob \ top of stack now has list of all "*.c" files, recursively
</syntaxhighlight>

=={{header|Ada}}==
<syntaxhighlight lang="ada">with Ada.Directories;  use Ada.Directories;
with Ada.Text_IO;

procedure Test_Directory_Walk is
   procedure Walk (Name : String; Pattern : String) is
      procedure Print (Item : Directory_Entry_Type) is
      begin
         Ada.Text_IO.Put_Line (Full_Name (Item));
      end Print;
      procedure Walk (Item : Directory_Entry_Type) is
      begin
         if Simple_Name (Item) /= "." and then Simple_Name (Item) /= ".." then
            Walk (Full_Name (Item), Pattern);
         end if;
      exception
         when Name_Error => null;
      end Walk;
   begin
      Search (Name, Pattern, (others => True), Print'Access);
      Search (Name, "", (Directory => True, others => False), Walk'Access);
   end Walk;
begin
   Walk (".", "*.adb");
end Test_Directory_Walk;</syntaxhighlight>
The solution first enumerates files in a directory, that includes the subdirectories, if their names match the pattern. Then it steps down into each of the subdirectories. The pseudo directories . and .. are excluded. The behavior upon symbolic links depends on the [[OS]] and the implementation of the Ada.Directories package.

=={{header|ALGOL 68}}==
<!-- {{does not work with|ALGOL 68|Standard - extensions to language used}} -->
{{works with|ALGOL 68G|Any - tested with release mk15-0.8b.fc9.i386 - uses non-standard library routines ''get directory'' and'' grep in string''.}}
<!-- {{does not work with|ELLA ALGOL 68|Any (with appropriate job cards) - tested with release 1.8.8d.fc9.i386 - ''get directory'' and'' grep in string'' not available in any library ... yet}} -->
<syntaxhighlight lang="algol68">INT match=0, no match=1, out of memory error=2, other error=3;

STRING slash = "/", pwd=".", parent="..";

PROC walk tree = (STRING path, PROC (STRING)VOID call back)VOID: (
  []STRING files = get directory(path);
  FOR file index TO UPB files DO
    STRING file = files[file index];
    STRING path file = path+slash+file;
    IF file is directory(path file) THEN
      IF file NE pwd AND file NE parent THEN
        walk tree(path file, call back)
      FI
    ELSE
      call back(path file)
    FI
  OD
);

STRING re sort a68 = "[Ss]ort[^/]*[.]a68$";

PROC match sort a68 and print = (STRING path file)VOID:
  IF grep in string(re sort a68, path file, NIL, NIL) = match THEN
    print((path file, new line))
  FI;

walk tree(".", match sort a68 and print)</syntaxhighlight>
{{out|Sample output}}
<pre>
./Shell_sort_c.a68
./Quick_sort.a68
./Shell_sort.a68
./Cocktail_Sort.a68
./Selection_Sort.a68
./Merge_sort.a68
./tmp/test_sort.a68
./Bobosort.a68
./Sorting_an_Array_of_Integers.a68
./Insertion_Sort.a68
./Permutation_Sort.a68
</pre>

=={{header|Arturo}}==

<syntaxhighlight lang="rebol">; list all files at current path
print list.recursive "."

; get all files at given path
; and select only the ones we want

; just select the files with .md extension
select list.recursive "some/path" 
    => [".md" = extract.extension]

; just select the files that contain "test"
select list.recursive "some/path" 
    => [in? "test"]</syntaxhighlight>

=={{header|AutoHotkey}}==
Display all TMP files in Temp directory and its subdirectories.
<syntaxhighlight lang="autohotkey">Loop, %A_Temp%\*.tmp,,1
 out .= A_LoopFileName "`n"
MsgBox,% out</syntaxhighlight>

=={{header|BaCon}}==
This line will recursively walk though all directories starting from the current directory ".":
<syntaxhighlight lang="qbasic">PRINT WALK$(".", 1, ".+", TRUE, NL$)</syntaxhighlight>

=={{header|Batch File}}==
A sample code that displays all the EXE files in System32 directory recursively.
<syntaxhighlight lang="dos">dir /s /b "%windir%\System32\*.exe"</syntaxhighlight>
----
If you wanted to apply some command to each item in a directory tree, then use <code>FOR</code> with the switch <code>/R</code>. For example, to apply the ECHO command to every DLL file in C:\Windows\System32:
{{works with|Windows NT|4 or later (includes Windows XP and onward)}}
<syntaxhighlight lang="dos">FOR /R C:\Windows\System32 %%F IN (*.DLL) DO ECHO "%%F"</syntaxhighlight>
This can be done from outside a batch file (entered directly at the command prompt) by changing the double percent signs (%%) to single percents (%):
<syntaxhighlight lang="dos">FOR /R C:\Windows\System32 %F IN (*.DLL) DO ECHO "%F"</syntaxhighlight>

=={{header|BBC BASIC}}==
{{works with|BBC BASIC for Windows}}
<syntaxhighlight lang="bbcbasic">      directory$ = "C:\Windows\"
      pattern$ = "*.chm"
      PROClisttree(directory$, pattern$)
      END
      
      DEF PROClisttree(dir$, filter$)
      LOCAL dir%, sh%, res%
      DIM dir% LOCAL 317
      IF RIGHT$(dir$) <> "\" IF RIGHT$(dir$) <> "/" dir$ += "\"
      SYS "FindFirstFile", dir$ + filter$, dir% TO sh%
      IF sh% <> -1 THEN
        REPEAT
          IF (!dir% AND 16) = 0 PRINT dir$ + $$(dir%+44)
          SYS "FindNextFile", sh%, dir% TO res%
        UNTIL res% = 0
        SYS "FindClose", sh%
      ENDIF
      SYS "FindFirstFile", dir$ + "*", dir% TO sh%
      IF sh% <> -1 THEN
        REPEAT
          IF (!dir% AND 16) IF dir%?44 <> &2E THEN
            PROClisttree(dir$ + $$(dir%+44) + "\", filter$)
          ENDIF
          SYS "FindNextFile", sh%, dir% TO res%
        UNTIL res% = 0
        SYS "FindClose", sh%
      ENDIF
      ENDPROC</syntaxhighlight>

=={{header|C}}==
==={{libheader|POSIX}}===
{{works with|POSIX|.1-2001}}
<syntaxhighlight lang="c">#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <regex.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <err.h>

enum {
	WALK_OK = 0,
	WALK_BADPATTERN,
	WALK_NAMETOOLONG,
	WALK_BADIO,
};

#define WS_NONE		0
#define WS_RECURSIVE	(1 << 0)
#define WS_DEFAULT	WS_RECURSIVE
#define WS_FOLLOWLINK	(1 << 1)	/* follow symlinks */
#define WS_DOTFILES	(1 << 2)	/* per unix convention, .file is hidden */
#define WS_MATCHDIRS	(1 << 3)	/* if pattern is used on dir names too */

int walk_recur(char *dname, regex_t *reg, int spec)
{
	struct dirent *dent;
	DIR *dir;
	struct stat st;
	char fn[FILENAME_MAX];
	int res = WALK_OK;
	int len = strlen(dname);
	if (len >= FILENAME_MAX - 1)
		return WALK_NAMETOOLONG;

	strcpy(fn, dname);
	fn[len++] = '/';

	if (!(dir = opendir(dname))) {
		warn("can't open %s", dname);
		return WALK_BADIO;
	}

	errno = 0;
	while ((dent = readdir(dir))) {
		if (!(spec & WS_DOTFILES) && dent->d_name[0] == '.')
			continue;
		if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
			continue;

		strncpy(fn + len, dent->d_name, FILENAME_MAX - len);
		if (lstat(fn, &st) == -1) {
			warn("Can't stat %s", fn);
			res = WALK_BADIO;
			continue;
		}

		/* don't follow symlink unless told so */
		if (S_ISLNK(st.st_mode) && !(spec & WS_FOLLOWLINK))
			continue;

		/* will be false for symlinked dirs */
		if (S_ISDIR(st.st_mode)) {
			/* recursively follow dirs */
			if ((spec & WS_RECURSIVE))
				walk_recur(fn, reg, spec);

			if (!(spec & WS_MATCHDIRS)) continue;
		}

		/* pattern match */
		if (!regexec(reg, fn, 0, 0, 0)) puts(fn);
	}

	if (dir) closedir(dir);
	return res ? res : errno ? WALK_BADIO : WALK_OK;
}

int walk_dir(char *dname, char *pattern, int spec)
{
	regex_t r;
	int res;
	if (regcomp(&r, pattern, REG_EXTENDED | REG_NOSUB))
		return WALK_BADPATTERN;
	res = walk_recur(dname, &r, spec);
	regfree(&r);

	return res;
}

int main()
{
	int r = walk_dir(".", ".\\.c$", WS_DEFAULT|WS_MATCHDIRS);
	switch(r) {
	case WALK_OK:		break;
	case WALK_BADIO:	err(1, "IO error");
	case WALK_BADPATTERN:	err(1, "Bad pattern");
	case WALK_NAMETOOLONG:	err(1, "Filename too long");
	default:
		err(1, "Unknown error?");
	}
	return 0;
}</syntaxhighlight>
==={{libheader|BSD libc}}===
With the [http://www.openbsd.org/cgi-bin/man.cgi?query=fts&apropos=0&sektion=3&manpath=OpenBSD+Current&arch=i386&format=html fts(3)] functions from 4.4BSD, this program can sort the files, and can also detect cycles (when a link puts a directory inside itself). This program makes a ''logical traversal'' that follows symbolic links to directories.
{{works with|OpenBSD|4.9}}
<syntaxhighlight lang="c">#include <sys/types.h>
#include <err.h>
#include <errno.h>
#include <fnmatch.h>
#include <fts.h>
#include <string.h>
#include <stdio.h>

/* Compare files by name. */
int
entcmp(const FTSENT **a, const FTSENT **b)
{
	return strcmp((*a)->fts_name, (*b)->fts_name);
}

/*
 * Print all files in the directory tree that match the glob pattern.
 * Example: pmatch("/usr/src", "*.c");
 */
void
pmatch(char *dir, const char *pattern)
{
	FTS *tree;
	FTSENT *f;
	char *argv[] = { dir, NULL };

	/*
	 * FTS_LOGICAL follows symbolic links, including links to other
	 * directories. It detects cycles, so we never have an infinite
	 * loop. FTS_NOSTAT is because we never use f->statp. It uses
	 * our entcmp() to sort files by name.
	 */
	tree = fts_open(argv, FTS_LOGICAL | FTS_NOSTAT, entcmp);
	if (tree == NULL)
		err(1, "fts_open");

	/*
	 * Iterate files in tree. This iteration always skips
	 * "." and ".." because we never use FTS_SEEDOT.
	 */
	while ((f = fts_read(tree))) {
		switch (f->fts_info) {
		case FTS_DNR:	/* Cannot read directory */
		case FTS_ERR:	/* Miscellaneous error */
		case FTS_NS:	/* stat() error */
			/* Show error, then continue to next files. */
			warn("%s", f->fts_path);
			continue;
		case FTS_DP:
			/* Ignore post-order visit to directory. */
			continue;
		}

		/*
		 * Check if name matches pattern. If so, then print
		 * path. This check uses FNM_PERIOD, so "*.c" will not
		 * match ".invisible.c".
		 */
		if (fnmatch(pattern, f->fts_name, FNM_PERIOD) == 0)
			puts(f->fts_path);

		/*
		 * A cycle happens when a symbolic link (or perhaps a
		 * hard link) puts a directory inside itself. Tell user
		 * when this happens.
		 */
		if (f->fts_info == FTS_DC)
			warnx("%s: cycle in directory tree", f->fts_path);
	}

	/* fts_read() sets errno = 0 unless it has error. */
	if (errno != 0)
		err(1, "fts_read");

	if (fts_close(tree) < 0)
		err(1, "fts_close");
}

int
main()
{
	pmatch(".", "*.c");
	return 0;
}</syntaxhighlight>
=== [[Windows]] ===
{{libheader|Win32}}
{{works with|MinGW}}
<syntaxhighlight lang="c">#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>

/* Print "message: last Win32 error" to stderr. */
void
oops(const wchar_t *message)
{
	wchar_t *buf;
	DWORD error;

	buf = NULL;
	error = GetLastError();
	FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
	    FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
	    NULL, error, 0, (wchar_t *)&buf, 0, NULL);

	if (buf) {
		fwprintf(stderr, L"%ls: %ls", message, buf);
		LocalFree(buf);
	} else {
		/* FormatMessageW failed. */
		fwprintf(stderr, L"%ls: unknown error 0x%x\n",
		    message, error);
	}
}

/*
 * Print all files in a given directory tree that match a given wildcard
 * pattern.
 */
int
main()
{
	struct stack {
		wchar_t			*path;
		size_t			 pathlen;
		size_t			 slashlen;
		HANDLE			 ffh;
		WIN32_FIND_DATAW	 ffd;
		struct stack		*next;
	} *dir, dir0, *ndir;
	size_t patternlen;
	int argc;
	wchar_t **argv, *buf, c, *pattern;

	/* MinGW never provides wmain(argc, argv). */
	argv = CommandLineToArgvW(GetCommandLineW(), &argc);
	if (argv == NULL) {
		oops(L"CommandLineToArgvW");
		exit(1);
	}

	if (argc != 3) {
		fwprintf(stderr, L"usage: %ls dir pattern\n", argv[0]);
		exit(1);
	}

	dir0.path = argv[1];
	dir0.pathlen = wcslen(dir0.path);
	pattern = argv[2];
	patternlen = wcslen(pattern);

	if (patternlen == 0 ||
	    wcscmp(pattern, L".") == 0 ||
	    wcscmp(pattern, L"..") == 0 ||
	    wcschr(pattern, L'/') ||
	    wcschr(pattern, L'\\')) {
		fwprintf(stderr, L"%ls: invalid pattern\n", pattern);
		exit(1);
	}

	/*
	 * Must put backslash between path and pattern, unless
	 * last character of path is slash or colon.
	 *
	 *   'dir' => 'dir\*'
	 *   'dir\' => 'dir\*'
	 *   'dir/' => 'dir/*'
	 *   'c:' => 'c:*'
	 *
	 * 'c:*' and 'c:\*' are different files!
	 */
	c = dir0.path[dir0.pathlen - 1];
	if (c == ':' || c == '/' || c == '\\')
		dir0.slashlen = dir0.pathlen;
	else
		dir0.slashlen = dir0.pathlen + 1;

	/* Allocate space for path + backslash + pattern + \0. */
	buf = calloc(dir0.slashlen + patternlen + 1, sizeof buf[0]);
	if (buf == NULL) {
		perror("calloc");
		exit(1);
	}
	dir0.path = wmemcpy(buf, dir0.path, dir0.pathlen + 1);

	dir0.ffh = INVALID_HANDLE_VALUE;
	dir0.next = NULL;
	dir = &dir0;

	/* Loop for each directory in linked list. */
loop:
	while (dir) {
		/*
		 * At first visit to directory:
		 *   Print the matching files. Then, begin to find
		 *   subdirectories.
		 *
		 * At later visit:
		 *   dir->ffh is the handle to find subdirectories.
		 *   Continue to find them.
		 */
		if (dir->ffh == INVALID_HANDLE_VALUE) {
			/* Append backslash + pattern + \0 to path. */
			dir->path[dir->pathlen] = '\\';
			wmemcpy(dir->path + dir->slashlen,
			    pattern, patternlen + 1);

			/* Find all files to match pattern. */
			dir->ffh = FindFirstFileW(dir->path, &dir->ffd);
			if (dir->ffh == INVALID_HANDLE_VALUE) {
				/* Check if no files match pattern. */
				if (GetLastError() == ERROR_FILE_NOT_FOUND)
					goto subdirs;

				/* Bail out from other errors. */
				dir->path[dir->pathlen] = '\0';
				oops(dir->path);
				goto popdir;
			}

			/* Remove pattern from path; keep backslash. */
			dir->path[dir->slashlen] = '\0';

			/* Print all files to match pattern. */
			do {
				wprintf(L"%ls%ls\n",
				    dir->path, dir->ffd.cFileName);
			} while (FindNextFileW(dir->ffh, &dir->ffd) != 0);
			if (GetLastError() != ERROR_NO_MORE_FILES) {
				dir->path[dir->pathlen] = '\0';
				oops(dir->path);
			}
			FindClose(dir->ffh);

subdirs:
			/* Append * + \0 to path. */
			dir->path[dir->slashlen] = '*';
			dir->path[dir->slashlen + 1] = '\0';

			/* Find first possible subdirectory. */
			dir->ffh = FindFirstFileExW(dir->path,
			    FindExInfoStandard, &dir->ffd,
			    FindExSearchLimitToDirectories, NULL, 0);
			if (dir->ffh == INVALID_HANDLE_VALUE) {
				dir->path[dir->pathlen] = '\0';
				oops(dir->path);
				goto popdir;
			}
		} else {
			/* Find next possible subdirectory. */
			if (FindNextFileW(dir->ffh, &dir->ffd) == 0)
				goto closeffh;				
		}

		/* Enter subdirectories. */
		do {
			const wchar_t *fn = dir->ffd.cFileName;
			const DWORD attr = dir->ffd.dwFileAttributes;
			size_t buflen, fnlen;

			/*
			 * Skip '.' and '..', because they are links to
			 * the current and parent directories, so they
			 * are not subdirectories.
			 *
			 * Skip any file that is not a directory.
			 *
			 * Skip all reparse points, because they might
			 * be symbolic links. They might form a cycle,
			 * with a directory inside itself.
			 */
			if (wcscmp(fn, L".") == 0 ||
			    wcscmp(fn, L"..") == 0 ||
			    (attr & FILE_ATTRIBUTE_DIRECTORY) == 0 ||
			    (attr & FILE_ATTRIBUTE_REPARSE_POINT))
				continue;

			ndir = malloc(sizeof *ndir);
			if (ndir == NULL) {
				perror("malloc");
				exit(1);
			}

			/*
			 * Allocate space for path + backslash +
			 *     fn + backslash + pattern + \0.
			 */
			fnlen = wcslen(fn);
			buflen = dir->slashlen + fnlen + patternlen + 2;
			buf = calloc(buflen, sizeof buf[0]);
			if (buf == NULL) {
				perror("malloc");
				exit(1);
			}

			/* Copy path + backslash + fn + \0. */
			wmemcpy(buf, dir->path, dir->slashlen);
			wmemcpy(buf + dir->slashlen, fn, fnlen + 1);

			/* Push dir to list. Enter dir. */
			ndir->path = buf;
			ndir->pathlen = dir->slashlen + fnlen;
			ndir->slashlen = ndir->pathlen + 1;
			ndir->ffh = INVALID_HANDLE_VALUE;
			ndir->next = dir;
			dir = ndir;
			goto loop; /* Continue outer loop. */
		} while (FindNextFileW(dir->ffh, &dir->ffd) != 0);
closeffh:
		if (GetLastError() != ERROR_NO_MORE_FILES) {
			dir->path[dir->pathlen] = '\0';
			oops(dir->path);
		}
		FindClose(dir->ffh);

popdir:
		/* Pop dir from list, free dir, but never free dir0. */
		free(dir->path);
		if (ndir = dir->next)
			free(dir);
		dir = ndir;
	}

	return 0;
}</syntaxhighlight>

=={{header|C sharp|C#}}==
<syntaxhighlight lang="csharp">using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace RosettaRecursiveDirectory
{
    class Program
    {
        static IEnumerable<FileInfo> TraverseDirectory(string rootPath, Func<FileInfo, bool> Pattern)
        {
            var directoryStack = new Stack<DirectoryInfo>();
            directoryStack.Push(new DirectoryInfo(rootPath));
            while (directoryStack.Count > 0)
            {
                var dir = directoryStack.Pop();
                try
                {
                    foreach (var i in dir.GetDirectories())
                        directoryStack.Push(i);
                }
                catch (UnauthorizedAccessException) {
                    continue; // We don't have access to this directory, so skip it
                }
                foreach (var f in dir.GetFiles().Where(Pattern)) // "Pattern" is a function
                    yield return f;
            }
        }
        static void Main(string[] args)
        {
            // Print the full path of all .wmv files that are somewhere in the C:\Windows directory or its subdirectories
            foreach (var file in TraverseDirectory(@"C:\Windows", f => f.Extension == ".wmv"))
                Console.WriteLine(file.FullName);
            Console.WriteLine("Done.");
        }
    }
}
</syntaxhighlight>

=={{header|C++}}==
{{libheader|boost}}
<syntaxhighlight lang="cpp">#include "boost/filesystem.hpp"
#include "boost/regex.hpp"
#include <iostream>

using namespace boost::filesystem;

int main()
{
  path current_dir("."); //
  boost::regex pattern("a.*"); // list all files starting with a
  for (recursive_directory_iterator iter(current_dir), end;
       iter != end;
       ++iter)
  {
    std::string name = iter->path().filename().string();
    if (regex_match(name, pattern))
      std::cout << iter->path() << "\n";
  }
}</syntaxhighlight>

{{libheader|std|C++17}}
<syntaxhighlight lang="cpp">
#include <filesystem>
#include <iostream>

namespace fs = std::filesystem;

int main() {
  fs::path current_dir(".");
  // list all files containing an mp3 extension
  for (auto &file : fs::recursive_directory_iterator(current_dir)) {
    if (file.path().extension() == ".mp3")
      std::cout << file.path().filename().string() << std::endl;
  }
}</syntaxhighlight>

=={{header|Caché ObjectScript}}==

<syntaxhighlight lang="cos">
Class Utils.File [ Abstract ]
{

ClassMethod WalkTree(pDir As %String = "", pMask As %String = "*.*") As %Status
{
	// do some validation
	If pDir="" Quit $$$ERROR($$$GeneralError, "No directory specified.")
	
	// search input directory for files matching wildcard
	Set fs=##class(%ResultSet).%New("%File.FileSet")
	Set sc=fs.Execute(pDir, pMask)
	While (fs.Next()) {
		Write !, fs.Name
		// sub-directory
		If fs.Type="D" Set sc=..WalkTree(fs.Name, pMask)
	}
	
	// finished
	Quit $$$OK
}

}
</syntaxhighlight>

{{out|Example}}
<pre>
USER>Do ##class(Utils.File).WalkTree("/Swsetup/")

C:\Swsetup\Monitors
C:\Swsetup\Monitors\HP_w2207_3.0
C:\Swsetup\Monitors\HP_w2207_3.0\Files
C:\Swsetup\Monitors\HP_w2207_3.0\Files\HP_w2207.cat
C:\Swsetup\Monitors\HP_w2207_3.0\Files\HP_w2207.icm
C:\Swsetup\Monitors\HP_w2207_3.0\Files\HP_w2207.inf
C:\Swsetup\Monitors\HP_w2207_3.0\HP Display Installer.exe
C:\Swsetup\Monitors\HP_w2207_3.0\HPx64DRV.exe
C:\Swsetup\Monitors\HP_w2207_3.0\Readme.txt
</pre>

=={{header|Clojure}}==
The standard function ''file-seq'' does a tree walk.
<syntaxhighlight lang="clojure">(use '[clojure.java.io])

(defn walk [dirpath pattern]
  (doall (filter #(re-matches pattern (.getName %))
                 (file-seq (file dirpath)))))

(map #(println (.getPath %)) (walk "src" #".*\.clj"))
</syntaxhighlight>

=={{header|CoffeeScript}}==
{{works with|node.js}}
<syntaxhighlight lang="coffeescript">fs = require 'fs'

walk = (dir, f_match, f_visit) ->
  _walk = (dir) ->
    fns = fs.readdirSync dir
    for fn in fns
      fn = dir + '/' + fn
      if f_match fn
        f_visit fn
      if fs.statSync(fn).isDirectory()
        _walk fn
  _walk(dir)
  
dir = '..'
matcher = (fn) -> fn.match /\.coffee/
action = console.log
walk dir, matcher, action</syntaxhighlight>

=={{header|Common Lisp}}==
{{libheader|CL-FAD}}
This example uses the <code>CL-FAD</code> library to achieve compatibility where the ANSI CL standard leaves ambiguities about pathnames. Quicklisp is used to ensure it is loaded. Traversal is depth-first unless <code>:depth-first-p nil</code> is passed.
<syntaxhighlight lang="lisp">(ql:quickload :cl-fad)
(defun mapc-directory-tree (fn directory &key (depth-first-p t))
  (dolist (entry (cl-fad:list-directory directory))
    (unless depth-first-p
      (funcall fn entry))
    (when (cl-fad:directory-pathname-p entry)
      (mapc-directory-tree fn entry))
    (when depth-first-p
      (funcall fn entry))))
</syntaxhighlight>

<syntaxhighlight lang="lisp">CL-USER> (mapc-directory-tree (lambda (x)
                                (when (equal (pathname-type x) "lisp")
                                  (write-line (namestring x))))
                              "lang/")
/home/sthalik/lang/lisp/.#bitmap.lisp
/home/sthalik/lang/lisp/avg.lisp
/home/sthalik/lang/lisp/bitmap.lisp
/home/sthalik/lang/lisp/box-muller.lisp
/home/sthalik/lang/lisp/displaced-subseq.lisp
[...]</syntaxhighlight>

=={{header|D}}==
<syntaxhighlight lang="d">void main() {
    import std.stdio, std.file;

    // Recursive breadth-first scan (use SpanMode.depth for
    // a depth-first scan):
    dirEntries("", "*.d", SpanMode.breadth).writeln;
}</syntaxhighlight>

=={{header|Dart}}==
<syntaxhighlight lang="dart">
import 'dart:io' show Directory, Platform, File;

void main(List<String> args) {
  var dir = Directory(args[0]);
  dir.list(recursive: true, followLinks: false).forEach((final cur) {
    if (cur is Directory) {
      print("Directory: ${cur.path}");
    }

    if (cur is File) {
      print("File: ${cur.path}");
    }
  });
}
</syntaxhighlight>

=={{header|Delphi}}==
{{libheader| System.IOUtils}}
<syntaxhighlight lang="delphi">
program Walk_a_directory;

{$APPTYPE CONSOLE}
{$R *.res}

uses
  System.IOUtils;

var
  Files: TArray<string>;
  FileName, Directory: string;

begin
  Directory := TDirectory.GetCurrentDirectory;  // dir = '.', work to
  Files := TDirectory.GetFiles(Directory, '*.*', TSearchOption.soAllDirectories);

  for FileName in Files do
  begin
    Writeln(FileName);
  end;

  Readln;
end.

</syntaxhighlight>
=={{header|E}}==
<syntaxhighlight lang="e">def walkTree(directory, pattern) {
  for name => file in directory {
    if (name =~ rx`.*$pattern.*`) {
      println(file.getPath())
    }
    if (file.isDirectory()) {
      walkTree(file, pattern)
    }
  }
}</syntaxhighlight>
{{out|Example}}
<syntaxhighlight lang="e">? walkTree(<file:/usr/share/man>, "rmdir")
/usr/share/man/man1/rmdir.1
/usr/share/man/man2/rmdir.2</syntaxhighlight>

=={{header|Elixir}}==
<syntaxhighlight lang="elixir">defmodule Walk_directory do
  def recursive(dir \\ ".") do
    Enum.each(File.ls!(dir), fn file ->
      IO.puts fname = "#{dir}/#{file}"
      if File.dir?(fname), do: recursive(fname)
    end)
  end
end

Walk_directory.recursive</syntaxhighlight>

{{out}}
<pre>
./check.exs
./e.bat
./foo
./foo/bar
./foo/bar/1
./foo/bar/2
./foo/bar/a
./foo/bar/b
./input.txt
./test.beam
./test.exs
./test.txt
</pre>

=={{header|Emacs Lisp}}==
<syntaxhighlight lang="lisp">ELISP> (directory-files-recursively "/tmp/el" "\\.el$")
("/tmp/el/1/c.el" "/tmp/el/a.el" "/tmp/el/b.el")</syntaxhighlight>

=={{header|Erlang}}==
Use the builtin function [http://erlang.org/doc/man/filelib.html#fold_files-5 filelib:fold_files/5].

{{out}}
<syntaxhighlight lang="erlang">
walk_dir(Path, Pattern) ->
        filelib:fold_files(
                Path,
                Pattern,
                true, % Recurse
                fun(File, Accumulator) -> [File|Accumulator] end,
                []
        )
</syntaxhighlight>

<syntaxhighlight lang="erlang">
% Collect every file in the current directory
walkdir:walk_dir(".", ".*").

% Collect every file my .config folder that ends with `rc`
walkdir:walk_dir("/home/me/.config/", ".*rc$").
</syntaxhighlight>

=={{header|F_Sharp|F#}}==
This code is tail-recursive and lazy.
<syntaxhighlight lang="fsharp">open System.IO

let rec getAllFiles dir pattern =
    seq { yield! Directory.EnumerateFiles(dir, pattern)
          for d in Directory.EnumerateDirectories(dir) do
              yield! getAllFiles d pattern }

getAllFiles "c:\\temp" "*.xml"
|> Seq.iter (printfn "%s")</syntaxhighlight>

=={{header|Factor}}==
<syntaxhighlight lang="factor">USE: io.directories.search

"." t [
    dup ".factor" tail? [ print ] [ drop ] if
] each-file</syntaxhighlight>

=={{header|Forth}}==
{{works with|gforth|0.7.9}}
<syntaxhighlight lang="forth">
require unix/filestat.fs
require unix/libc.fs

: $append ( from len to -- )   2DUP >R >R  COUNT + SWAP MOVE  R> R@ C@ + R> C! ;

defer ls-filter

: dots? ( name len -- ? )   drop c@ [char] . = ;

file-stat buffer: statbuf

: isdir ( addr u -- flag )
    statbuf lstat ?ior  statbuf st_mode w@ S_IFMT and S_IFDIR = ;

: (ls-r) ( dir len -- )
  pad c@ >r  pad $append  s" /" pad $append
  pad count open-dir if  drop  r> pad c!  exit  then  ( dirid)
  begin
    dup pad count + 256 rot read-dir throw
  while
    pad count + over dots? 0= if   \ ignore all hidden names
      dup pad count rot + 2dup ls-filter if
        cr 2dup type
      then
      isdir if
        pad count + swap recurse
      else drop then
    else drop then 
  repeat
  drop  r> pad c!
  close-dir throw
;

: ls-r ( dir len -- )  0 pad c!  (ls-r) ;

: c-files ( str len -- ? )
  dup 3 < if 2drop false exit then
  + 1- dup c@ 32 or
   dup [char] c <> swap [char] h <> and if drop false exit then
  1- dup c@ [char] . <> if drop false exit then
  drop true ;
' c-files is ls-filter

: all-files ( str len -- ? )   2drop true ;
' all-files is ls-filter

s" ." ls-r cr
</syntaxhighlight>


=={{header|FreeBASIC}}==
<syntaxhighlight lang="freebasic">#include "dir.bi"

Sub listFiles(Byref filespec As String, Byval attrib As Integer)
    Dim As Integer count = 0
    Dim As String filename = Dir(filespec, attrib)
    Do While Len(filename) > 0
        count += 1
        Print filename
        filename = Dir()
    Loop
    Print !"\nArchives count:"; count
End Sub

Dim As String mylist = "C:\FreeBASIC\""
Print "Directories:"
listFiles(mylist & "*", fbDirectory)
Print
Print "Archive files:"
listFiles(mylist & "*", fbArchive)
Sleep</syntaxhighlight>

=={{header|FutureBasic}}==
<syntaxhighlight lang="futurebasic">
include "NSLog.incl"

void local fn EnumerateDirectoryAtURL( dirURL as CFURLRef )
  NSDirectoryEnumerationOptions options = NSDirectoryEnumerationSkipsPackageDescendants + ¬
  NSDirectoryEnumerationSkipsHiddenFiles
    
  DirectoryEnumeratorRef enumerator = fn FileManagerEnumeratorAtURL( dirURL, NULL, options, NULL, NULL )
  CFURLRef url = fn EnumeratorNextObject( enumerator )
  while ( url )
    if ( fn StringIsEqual( fn URLPathExtension( url ), @"fb" ) )
      NSLog(@"%@",url)
    end if
    url = fn EnumeratorNextObject( enumerator )
  wend
end fn

fn EnumerateDirectoryAtURL( fn FileManagerURLForDirectory( NSDesktopDirectory, NSUserDomainMask ) )

HandleEvents
</syntaxhighlight>

=={{header|Gambas}}==
'''[https://gambas-playground.proko.eu/?gist=f48f8d5c2e2e85a8f80bcdc0124a35a5 Click this link to run this code]'''
<syntaxhighlight lang="gambas">Public Sub Main()
Dim sTemp As String
 
For Each sTemp In RDir("/etc", "*.d")
  Print sTemp
Next

End</syntaxhighlight>
Output:
<pre>
sysctl.d
systemd/ntp-units.d
pam.d
security/limits.d
security/namespace.d
insserv.conf.d
udev/hwdb.d
....
</pre>

=={{header|GAP}}==
<syntaxhighlight lang="gap">Walk := function(name, op)
	local dir, file, e;
	dir := Directory(name);
	for e in SortedList(DirectoryContents(name)) do
		file := Filename(dir, e);
		if IsDirectoryPath(file) then
			if not (e in [".", ".."]) then
				Walk(file, op);
			fi;
		else
			op(file);
		fi;
	od;
end;

# This will print filenames
Walk(".", Display);</syntaxhighlight>

=={{header|Go}}==
<syntaxhighlight lang="go">package main

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

func VisitFile(fp string, fi os.FileInfo, err error) error {
    if err != nil {
        fmt.Println(err) // can't walk here,
        return nil       // but continue walking elsewhere
    }
    if fi.IsDir() {
        return nil // not a file.  ignore.
    }
    matched, err := filepath.Match("*.mp3", fi.Name())
    if err != nil {
        fmt.Println(err) // malformed pattern
        return err       // this is fatal.
    }
    if matched {
        fmt.Println(fp)
    }
    return nil
}

func main() {
    filepath.Walk("/", VisitFile)
}</syntaxhighlight>

=={{header|Groovy}}==
Search text files in current directory tree in a depth-first fashion:

<syntaxhighlight lang="groovy">new File('.').eachFileRecurse {
  if (it.name =~ /.*\.txt/) println it;
}</syntaxhighlight>

Shorter variant:
<syntaxhighlight lang="groovy">new File('.').eachFileRecurse ~/.*\.txt/, { println it }</syntaxhighlight>

Variant processing only files:
<syntaxhighlight lang="groovy">new File('.').eachFileRecurse FILES, ~/.*\.txt/, { println it }</syntaxhighlight>

Flexible search, traversal can be adapted by providing various options in the options Map, see documentation of method:
[http://docs.groovy-lang.org/latest/html/groovy-jdk/java/io/File.html#traverse(java.util.Map,%20groovy.lang.Closure) traverse(Map options, Closure closure)]
<syntaxhighlight lang="groovy">new File('.').traverse(
    type         : FILES,
    nameFilter   : ~/.*\.txt/,
    preDir       : { if (it.name == '.svn') return SKIP_SUBTREE },
) { println it }
</syntaxhighlight>

=={{header|GUISS}}==
Here we list all files that match the pattern m*.txt in "My Documents" and all of its subfolders:
<syntaxhighlight lang="guiss">Start,Find,Files and Folders,Dropdown: Look in>My Documents,
Inputbox: filename>m*.txt,Button:Search</syntaxhighlight>

=={{header|Haskell}}==

Using the packages [http://hackage.haskell.org/package/directory-1.2.5.0/docs/System-Directory.html#v:getCurrentDirectory directory] and [https://hackage.haskell.org/package/filemanip-0.3.6.3/docs/System-FilePath-Find.html#v:find filemanip]

<syntaxhighlight lang="haskell">import System.Environment
import System.Directory
import System.FilePath.Find

search pat = find always (fileName ~~? pat)

main = do
  [pat] <- getArgs
  dir <- getCurrentDirectory
  files <- search pat dir
  mapM_ putStrLn files</syntaxhighlight>
or more classic way:
<syntaxhighlight lang="haskell">import System.FilePath.Posix
import System.Directory
import System.IO

dirWalk :: (FilePath -> IO ()) -> FilePath -> IO ()
dirWalk filefunc top = do
  isDirectory <- doesDirectoryExist top
  if isDirectory
    then do
      files <- listDirectory top
      mapM_ (dirWalk filefunc . (top </>)) files
    else filefunc top

main :: IO ()
main = do
  hSetEncoding stdout utf8
  hSetEncoding stdin utf8
  let worker fname
        | takeExtension fname == ".hs" = putStrLn fname
        | otherwise = return ()
  dirWalk worker "."</syntaxhighlight>

== Icon and Unicon ==
==={{header|Icon}}===
Icon doesn't support 'stat' or 'open' of a directory; however, information can be obtained by use of the <code>system</code> function to access command line. 
==={{header|Unicon}}===
<syntaxhighlight lang="unicon">
########################### 
#  A sequential solution  #
###########################

procedure main()
every write(!getdirs("."))  # writes out all directories from the current directory down
end

procedure getdirs(s)  #: return a list of directories beneath the directory 's'
local D,d,f

if ( stat(s).mode ? ="d" ) & ( d := open(s) ) then {
      D := [s]
      while f := read(d) do 
         if not ( ".." ? =f ) then          # skip . and ..
            D |||:= getdirs(s || "/" ||f)
      close(d)
      return D
      }
end

######################### 
#  A threaded solution  #
#########################

import threads

global n,           # number of the concurrently running threads
       maxT,        # Max number of concurrent threads ("soft limit")
       tot_threads  # the total number of threads created in the program

procedure main(argv)
   target := argv[1] | stop("Usage: tdir [dir name] [#threads]. #threads default to 2* the number of cores in the machine.")
   tot_threads := n := 1 
   maxT := ( integer(argv[2])|
	    (&features? if ="CPU cores " then cores := integer(tab(0)) * 2) | # available cores * 2
   	    4) # default to 4 threads
   t := milliseconds()
   L := getdirs(target)  # writes out all directories from the current directory down
   write((*\L)| 0, " directories in ", milliseconds() - t, 
	           " ms using ", maxT, "-concurrent/", tot_threads, "-total threads" )
end

procedure getdirs(s)  # return a list of directories beneath the directory 's'
local D,d,f, thrd

if ( stat(s).mode ? ="d" ) & ( d := open(s) ) then {
      D := [s]
      while f := read(d) do 
         if not ( ".." ? =f ) then          # skip . and ..
            if n>=maxT then # max thread count reached
               D |||:= getdirs(s || "/" ||f)
            else # spawn a new thread for this directory
	       {/thrd:=[]; n +:= 1; put(thrd, thread getdirs(s || "/" ||f))}
      
      close(d)

      if \thrd then{  # If I have threads, collect their results
         tot_threads +:= *thrd
         n -:= 1      # allow new threads to be spawned while I'm waiting/collecting results
	 every wait(th := !thrd) do { # wait for the thread to finish
	    n -:= 1        
	    D |||:= <@th   # If the thread produced a result, it is going to be
	                   # stored in its "outbox", <@th in this case serves as
	                   # a deferred return since the thread was created by
			   # thread getdirs(s || "/" ||f)
	                   # this is similar to co-expression activation semantics
            }
         n +:= 1
         }
      return D
      }
end</syntaxhighlight>

=={{header|IDL}}==
<syntaxhighlight lang="idl">result = file_search( directory, '*.txt', count=cc )</syntaxhighlight>
This will descend down the directory/ies in the variable <tt>"directory"</tt> (which can be an array) returning an array of strings with the names of the files matching "*.txt" and placing the total number of matches into the variable <tt>"cc"</tt>

=={{header|J}}==
<syntaxhighlight lang="j">require 'dir'
>{."1 dirtree '*.html'</syntaxhighlight>

The verb <tt>dirtree</tt> returns a file listing of a directory tree as a boxed matrix with file names in the first column. The primitives <tt>>{."1</tt> will return the unboxed contents of the first column.

'*.html' can be replaced by another pattern, of course.

=={{header|Java}}==
{{works with|Java|1.4+}}
Done using no pattern. But with end string comparison which gave better results.
<syntaxhighlight lang="java">import java.io.File;

public class MainEntry {
    public static void main(String[] args) {
        walkin(new File("/home/user")); //Replace this with a suitable directory
    }
    
    /**
     * Recursive function to descend into the directory tree and find all the files 
     * that end with ".mp3"
     * @param dir A file object defining the top directory
     **/
    public static void walkin(File dir) {
        String pattern = ".mp3";
        
        File listFile[] = dir.listFiles();
        if (listFile != null) {
            for (int i=0; i<listFile.length; i++) {
                if (listFile[i].isDirectory()) {
                    walkin(listFile[i]);
                } else {
                    if (listFile[i].getName().endsWith(pattern)) {
                        System.out.println(listFile[i].getPath());
                    }
                }
            }
        }
    }
}</syntaxhighlight>
{{works with|Java|7+}}
Luckily, <code>java.nio.file.Files</code> gives us a <code>walkFileTree</code> method that does exactly what this task calls for.
<syntaxhighlight lang="java5">import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
 
public class WalkTree {
	public static void main(String[] args) throws IOException {
		Path start = FileSystems.getDefault().getPath("/path/to/file");
		Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
			@Override
			public FileVisitResult visitFile(Path file,
					BasicFileAttributes attrs) throws IOException {
				if (file.toString().endsWith(".mp3")) {
					System.out.println(file);
				}
				return FileVisitResult.CONTINUE;
			}
		});
	}
}</syntaxhighlight>
{{works with|Java|8+}}
<syntaxhighlight lang="java">import java.io.IOException;
import java.nio.file.*;

public class WalkTree {
	public static void main(String[] args) throws IOException {
		Path start = FileSystems.getDefault().getPath("/path/to/file");
		Files.walk(start)
		     .filter( path -> path.toFile().isFile())
		     .filter( path -> path.toString().endsWith(".mp3"))
		     .forEach( System.out::println );
	}
}
</syntaxhighlight>

=={{header|JavaScript}}==
{{works with|JScript}}
<syntaxhighlight lang="javascript">var fso = new ActiveXObject("Scripting.FileSystemObject");

function walkDirectoryTree(folder, folder_name, re_pattern) {
    WScript.Echo("Files in " + folder_name + " matching '" + re_pattern + "':");
    walkDirectoryFilter(folder.files, re_pattern);

    var subfolders = folder.SubFolders;
    WScript.Echo("Folders in " + folder_name + " matching '" + re_pattern + "':");
    walkDirectoryFilter(subfolders, re_pattern);

    WScript.Echo();
    var en = new Enumerator(subfolders);
    while (! en.atEnd()) {
        var subfolder = en.item();
        walkDirectoryTree(subfolder, folder_name + "/" + subfolder.name, re_pattern);
        en.moveNext();
    }
}

function walkDirectoryFilter(items, re_pattern) {
    var e = new Enumerator(items);
    while (! e.atEnd()) {
        var item = e.item();
        if (item.name.match(re_pattern))
            WScript.Echo(item.name);
        e.moveNext();
    }
}

walkDirectoryTree(dir, dir.name, '\\.txt$');</syntaxhighlight>

=={{header|Julia}}==
{{works with|Julia|1.2}}

<syntaxhighlight lang="julia">rootpath = "/home/user/music"
pattern  = r".mp3$"

for (root, dirs, files) in walkdir(rootpath)
    for file in files
        if occursin(pattern, file) println(file) end
    end
end</syntaxhighlight>

=={{header|Kotlin}}==
<syntaxhighlight lang="scala">// version 1.2.0

import java.io.File

fun walkDirectoryRecursively(dirPath: String, pattern: Regex): Sequence<String> {
    val d = File(dirPath)
    require (d.exists() && d.isDirectory())
    return d.walk().map { it.name }.filter { it.matches(pattern) }.sorted().distinct() }

fun main(args: Array<String>) {
    val r = Regex("""^v(a|f).*\.h$""")  // get all C header files beginning with 'va' or 'vf'
    val files = walkDirectoryRecursively("/usr/include", r)
    for (file in files) println(file)
}
</syntaxhighlight>

Output (Ubuntu 14.04):
<pre>
valarray_after.h
valarray_array.h
valarray_before.h
values.h
vfio.h
vfs.h
</pre>

=={{header|Lasso}}==
<syntaxhighlight lang="lasso">// care only about visible files and filter out any directories
define dir -> eachVisibleFilePath() => {
	return with name in self -> eachEntry where #name -> second != io_dir_dt_dir where not(#name -> first  ->  beginswith('.')) select .makeFullPath(#name -> first)
}

// care only about visible directories and filter out any files
define dir -> eachVisibleDir() => {
	return with name in self -> eachEntry where #name -> second == io_dir_dt_dir where not(#name -> first -> beginswith('.')) select dir(.makeFullPath(#name -> first + '/'))
}

// Recursively walk the directory tree and find all files and directories
// return only paths to files
define dir -> eachVisibleFilePathRecursive(-dirFilter = void) => {
	local(files = .eachVisibleFilePath)
	with dir in .eachVisibleDir
	where !#dirFilter || #dirFilter(#dir -> realPath)
	do {
		#files = tie(#files, #dir -> eachVisibleFilePathRecursive(-dirFilter = #dirFilter))
	}
	return #files
}

local(matchingfilenames = array)

with filepath in dir('/') -> eachVisibleFilePathRecursive
where #filepath -> endswith('.lasso')
let filename = #filepath -> split('/') -> last
do #matchingfilenames -> insert(#filename)

#matchingfilenames</syntaxhighlight>
-> array(myfile.lasso, test.lasso, rosetta.lasso)

=={{header|LiveCode}}==
<syntaxhighlight lang="livecode">function pathsForDirectoryAndWildcardPattern pDirectory, pWildcardPattern
   -- returns a return-delimited list of long file names
   -- the last character in the list is a return, unless the list is empty
   
   filter files(pDirectory) with pWildcardPattern
   repeat for each line tFile in it
      put pDirectory & slash & tFile & cr after tPaths
   end repeat
   
   filter folders(pDirectory) without ".."
   repeat for each line tFolder in it
      put pathsForDirectoryAndWildcardPattern(pDirectory & slash & tFolder, pWildcardPattern) after tPaths
   end repeat
   
   return tPaths
end pathsForDirectoryAndWildcardPattern</syntaxhighlight>

Example
<syntaxhighlight lang="livecode">put pathsForDirectoryAndWildcardPattern(the documents folder, "*.livecode*"</syntaxhighlight>
Output
<pre>...
/Users/xxx/Documents/abc.livecode
/Users/xxx/Documents/def.livecodescript
...</pre>
<nowiki>--~~~~</nowiki>

=={{header|Lua}}==
Lua itself is extremely spartanic as it is meant for embedding. As lfs (LuaFileSystem) is about as standard an extension as it gets, we use that.
<syntaxhighlight lang="lua">local lfs = require("lfs")

-- This function takes two arguments:
-- - the directory to walk recursively;
-- - an optional function that takes a file name as argument, and returns a boolean.
function find(self, fn)
  return coroutine.wrap(function()
    for f in lfs.dir(self) do
      if f ~= "." and f ~= ".." then
        local _f = self .. "/" .. f
        if not fn or fn(_f) then
          coroutine.yield(_f)
        end
        if lfs.attributes(_f, "mode") == "directory" then
          for n in find(_f, fn) do
            coroutine.yield(n)
          end
        end
      end
    end
  end)
end

-- Examples
-- List all files and directories
for f in find("directory") do
  print(f)
end

-- List lua files
for f in find("directory", function(self) return self:match("%.lua$") end) do
  print(f)
end

-- List directories
for f in find("directory", function(self) return "directory" == lfs.attributes(self, "mode") end) do
  print(f)
end</syntaxhighlight>

Lua provides functions such as os.execute([command]) and io.popen(prog [, mode]). Below an example for Windows users having io.popen at their disposal. Mind you, it may pop-up a command window.
<syntaxhighlight lang="lua">-- Gets the output of given program as string
-- Note that io.popen is not available on all platforms
local function getOutput(prog)
    local file = assert(io.popen(prog, "r"))
    local output = assert(file:read("*a"))
    file:close()
    return output
end

-- Iterates files in given directory
local function files(directory, recursively)
    -- Use windows" dir command
    local directory = directory:gsub("/", "\\")
    local filenames = getOutput(string.format("dir %s %s/B/A:A", directory, recursively and '/S' or ''))
    
    -- Function to be called in "for filename in files(directory)"
    return coroutine.wrap(function()
        for filename in filenames:gmatch("([^\r\n]+)") do
            coroutine.yield(filename)
        end    
    end)
end

-- Walk "C:/Windows" looking for executables
local directory = "C:/Windows"
local pattern = ".*%.exe$" -- for finding executables
for filename in files(directory, true) do
    if filename:match(pattern) then
        print(filename)
    end
end</syntaxhighlight>

=={{header|Mathematica}}/{{header|Wolfram Language}}==
The built-in function <code>FileNames</code> does exactly this:
:<code>FileNames[]</code> lists all files in the current working directory.
:<code>FileNames[form]</code> lists all files in the current working directory whose names match the string pattern form.
:<code>FileNames[{form1,form2,...}]</code> lists all files whose names match any of the form_i.
:<code>FileNames[forms,{dir1,dir2,...}]</code> lists files with names matching forms in any of the directories dir_i.
:<code>FileNames[forms,dirs,n]</code> includes files that are in subdirectories up to n levels down.
Examples (find all files in current directory, find all png files in root directory, find all files on the hard drive):
<syntaxhighlight lang="mathematica">FileNames["*"]
FileNames["*.png", $RootDirectory]
FileNames["*", {"*"}, Infinity]</syntaxhighlight>
the result can be printed with Print /@ FileNames[....]

=={{header|MATLAB}} / {{header|Octave}}==
<syntaxhighlight lang="matlab">function walk_a_directory_recursively(d, pattern)
	f = dir(fullfile(d,pattern));
	for k = 1:length(f)
		fprintf('%s\n',fullfile(d,f(k).name));
	end;

	f = dir(d);
	n = find([f.isdir]);	
	for k=n(:)'
		if any(f(k).name~='.') 
			walk_a_directory_recursively(fullfile(d,f(k).name), pattern);
		end;
	end;
end; </syntaxhighlight>

=={{header|MAXScript}}==
<syntaxhighlight lang="maxscript">fn walkDir dir pattern =
(
    dirArr = GetDirectories (dir + "\\*")

    for d in dirArr do
    (
        join dirArr (getDirectories (d + "\\*"))
    )

    append dirArr (dir + "\\") -- Need to include the original top level directory

    for f in dirArr do
    (
        print (getFiles (f + pattern))
    )
)

walkDir "C:" "*.txt"</syntaxhighlight>

=={{header|MoonScript}}==
MoonScript compiles to Lua, which itself is extremely spartanic as it is meant for embedding. As lfs (LuaFileSystem) is about as standard an extension as it gets, we use that.

<syntaxhighlight lang="moonscript">lfs = require "lfs"

-- This function takes two arguments:
-- - the directory to walk recursively;
-- - an optional function that takes a file name as argument, and returns a boolean.
find = (fn) => coroutine.wrap ->
  for f in lfs.dir @
    if f ~= "." and f ~= ".."
      _f = @.."/"..f
      coroutine.yield _f if not fn or fn _f
      if lfs.attributes(_f, "mode") == "directory"
        coroutine.yield n for n in find _f, fn

-- Examples
-- List all files
print f for f in find "templates"

-- List moonscript files
print f for f in find "templates", => @\match "%.moon$"

-- List directories
print f for f in find "templates", => "directory" == lfs.attributes @, "mode"</syntaxhighlight>

=={{header|Nanoquery}}==
<syntaxhighlight lang="nanoquery">import Nanoquery.IO

def get_files(dirname)
	local_filenames = new(File).listDir(dirname)

	filenames = {}

	for i in range(0, len(local_filenames) - 1)
		if len(local_filenames) > 0
			if not new(File, local_filenames[i]).isDir()
				filenames.append(local_filenames[i])
			else
				filenames += get_files(local_filenames[i])
			end
		end
	end

	return filenames
end

f = new(File)
for file in get_files("/")
	if lower(f.getExtension(file)) = ".mp3"
		println file
	end
end</syntaxhighlight>

=={{header|Nim}}==
The “os” standard module provides an iterator to walk recursively a directory. The iterator allows some filtering about the kind of entry to consider: real files (default), symbolic links to files, directories, symbolic links to directories. It doesn’t allow to specify a pattern, so filtering on name should be done using another mechanism (for instance, regular expressions).

<syntaxhighlight lang="nim">import os, re

for file in walkDirRec "/":
  if file.match re".*\.mp3":
    echo file</syntaxhighlight>

=={{header|Objeck}}==
<syntaxhighlight lang="objeck">use System.IO.File;

class Test {
  function : Main(args : String[]) ~ Nil {
    if(args->Size() = 2) {
      DescendDir(args[0], args[1]);
    };
  }

  function : DescendDir(path : String, pattern : String) ~ Nil {
    files := Directory->List(path);
    each(i : files) {
      file := files[i];
      if(<>file->StartsWith('.')) {
        dir_path := String->New(path);
        dir_path += '/';
        dir_path += file;
        
        if(Directory->Exists(dir_path)) {
          DescendDir(dir_path, pattern);
        }
        else if(File->Exists(dir_path) & dir_path->EndsWith(pattern)) {
          dir_path->PrintLine();
        };
      };
    };
  }
}</syntaxhighlight>

=={{header|Objective-C}}==
<syntaxhighlight lang="objc">NSString *dir = NSHomeDirectory();
NSDirectoryEnumerator *de = [[NSFileManager defaultManager] enumeratorAtPath:dir];

for (NSString *file in de)
  if ([[file pathExtension] isEqualToString:@"mp3"])
    NSLog(@"%@", file);</syntaxhighlight>

=={{header|OCaml}}==
<syntaxhighlight lang="ocaml">#!/usr/bin/env ocaml
#load "unix.cma"
#load "str.cma"
open Unix

let walk_directory_tree dir pattern =
  let re = Str.regexp pattern in (* pre-compile the regexp *)
  let select str = Str.string_match re str 0 in
  let rec walk acc = function
  | [] -> (acc)
  | dir::tail ->
      let contents = Array.to_list (Sys.readdir dir) in
      let contents = List.rev_map (Filename.concat dir) contents in
      let dirs, files =
        List.fold_left (fun (dirs,files) f ->
             match (stat f).st_kind with
             | S_REG -> (dirs, f::files)  (* Regular file *)
             | S_DIR -> (f::dirs, files)  (* Directory *)
             | _ -> (dirs, files)
          ) ([],[]) contents
      in
      let matched = List.filter (select) files in
      walk (matched @ acc) (dirs @ tail)
  in
  walk [] [dir]
;;

let () =
  let results = walk_directory_tree "/usr/local/lib/ocaml"  ".*\\.cma" in
  List.iter print_endline results;
;;</syntaxhighlight>

=={{header|ooRexx}}==
===version 1===
<syntaxhighlight lang="oorexx">/* REXX ---------------------------------------------------------------
* List all file names on my disk D: that contain the string TTTT
*--------------------------------------------------------------------*/
call SysFileTree "d:\*.*", "file", "FS" -- F get all Files
                                        -- S search subdirectories
Say file.0 'files on disk'
do i=1 to file.0
  If pos('TTTT',translate(file.i))>0 Then
    say file.i
  end</syntaxhighlight>
{{out}}
<pre>1127869 files on disk
 1/21/15  10:31p         340  A----  d:\tttt.txt
 1/21/15  10:37p           8  A----  d:\test\test2\test3\attttb.txt
 1/21/15  10:32p         340  A----  d:\_l\TtTttt.txt</pre>
===version 2===
Get only files matching the file-spec.
<syntaxhighlight lang="oorexx">/* REXX ---------------------------------------------------------------
* List all file names on my disk D: that contain the string TTTT
*--------------------------------------------------------------------*/
call SysFileTree "*TTTT*.*", "file", "FS" -- F get all Files
                                        -- S search subdirectories
Say file.0 'files found'
do i=1 to file.0
  If pos('TTTT',translate(file.i))>0 Then
    say file.i
  end    </syntaxhighlight>
{{out}}
<pre>3 files found
 1/21/15  10:31p         340  A----  D:\tttt.txt
 1/21/15  10:37p           8  A----  D:\test\test2\test3\attttb.txt
 1/21/15  10:32p         340  A----  D:\_l\TtTttt.txt     </pre>

=={{header|Oz}}==
<syntaxhighlight lang="oz">declare
  [Path] = {Module.link ['x-oz://system/os/Path.ozf']}
  [Regex] = {Module.link ['x-oz://contrib/regex']}

  proc {WalkDirTree Root Pattern Proc}
     proc {Walk R}
        Entries = {Path.readdir R}
        Files = {Filter Entries Path.isFile}
        MatchingFiles = {Filter Files fun {$ File} {Regex.search Pattern File} \= false end}
        Subdirs = {Filter Entries Path.isDir}
     in
        {ForAll MatchingFiles Proc}
        {ForAll Subdirs Walk}
     end
  in
     {Walk Root}
  end
in
  {WalkDirTree "." ".*\\.oz$" System.showInfo}</syntaxhighlight>

=={{header|Perl}}==

Use the <tt>File::Find</tt> module from CPAN:

{{works with|Perl|5.x}}
<syntaxhighlight lang="perl">use File::Find qw(find);
my $dir      = '.';
my $pattern  = 'foo';
my $callback = sub { print $File::Find::name, "\n" if /$pattern/ };
find $callback, $dir;</syntaxhighlight>

Or if you need maximum performance and are on a 'nix system, open a pipe to the GNU <tt>find</tt> program:

<syntaxhighlight lang="perl">sub shellquote { "'".(shift =~ s/'/'\\''/gr). "'" }

sub find_files {
    my $dir = shellquote(shift);
    my $test = shellquote(shift);
    
    local $/ = "\0";
    open my $pipe, "find $dir -iname $test -print0 |" or die "find: $!.\n";
    while (<$pipe>) { print "$_\n"; }  # Here you could do something else with each file path, other than simply printing it.
    close $pipe;
}

find_files('.', '*.mp3');</syntaxhighlight>

Or using the recently popular Path::Tiny

<syntaxhighlight lang="perl">#!/usr/bin/perl

use strict; # https://rosettacode.org/wiki/Walk_a_directory/Recursively
use warnings;
use Path::Tiny;

path('.')->visit( sub {/\.c$/ and print "$_\n"}, {recurse => 1} );</syntaxhighlight>

=={{header|Phix}}==
{{libheader|Phix/basics}}
There is a builtin routine for this, walk_dir() - if interested you can find the full implementation in builtins\file.e (an autoinclude).

<!--<syntaxhighlight lang="phix">-->
 <span style="color: #008080;">function</span> <span style="color: #000000;">find_pfile</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">pathname</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">dirent</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #7060A8;">match</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"pfile.e"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dirent</span><span style="color: #0000FF;">[</span><span style="color: #000000;">D_NAME</span><span style="color: #0000FF;">])</span> <span style="color: #008080;">then</span>
 <span style="color: #000080;font-style:italic;">--      return pathname&dirent[D_NAME] -- as below</span>
         <span style="color: #0000FF;">?</span><span style="color: #000000;">pathname</span><span style="color: #0000FF;">&</span><span style="color: #008000;">"\\"</span><span style="color: #0000FF;">&</span><span style="color: #000000;">dirent</span><span style="color: #0000FF;">[</span><span style="color: #000000;">D_NAME</span><span style="color: #0000FF;">]</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #008080;">return</span> <span style="color: #000000;">0</span>           <span style="color: #000080;font-style:italic;">-- non-zero terminates scan</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
 
 <span style="color: #0000FF;">?</span><span style="color: #7060A8;">walk_dir</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"C:\\Program Files (x86)\\Phix"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">find_pfile</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<!--</syntaxhighlight>-->

Passing 1 as the third parameter makes it scan recursively.
{{out}}
<pre>
"C:\\Program Files (x86)\\Phix\\.hg\\store\\data\\builtins\\pfile.e.i"
"C:\\Program Files (x86)\\Phix\\builtins\\pfile.e"
0
</pre>
<small>[the final 0 is from the walk_dir() call, whereas both paths are printed from inside find_pfile()]</small>

=={{header|PHP}}==
<syntaxhighlight lang="php">function findFiles($dir = '.', $pattern = '/./'){
  $prefix = $dir . '/';
  $dir = dir($dir);
  while (false !== ($file = $dir->read())){
    if ($file === '.' || $file === '..') continue;
    $file = $prefix . $file;
    if (is_dir($file)) findFiles($file, $pattern);
    if (preg_match($pattern, $file)){
      echo $file . "\n";
    }
  }
}
findFiles('./foo', '/\.bar$/');</syntaxhighlight>
This implementation uses Perl compatible regular expressions to match the whole path of the file

===PHP BFS (Breadth First Search)===
<syntaxhighlight lang="php">/*
	This script performs a BFS search with recursion protection
	it is often faster to search using this method across a
	filesystem due to a few reasons:

	* filesystem is accessed in native node order
	* a recursive function is not required allowing infinate depth
	* multiple directory handles are not required
	* the file being searched for is often not that deep in the fs

	This method also leverages PHP array hashing to speed up loop
	detection while minimizing the amount of RAM used to track the
	search history.

	-Geoffrey McRae
	Released as open license for any use.
*/
if ($_SERVER['argc'] < 3) {
	printf(
		"\n" .
		"Usage: %s (path) (search) [stop]\n" .
		"	path	the path to search\n" .
		"	search	the filename to search for\n" .
		"	stop	stop when file found, default 1\n" .
		"\n"
		, $_SERVER['argv'][0]);
	exit(1);
}

$path   = $_SERVER['argv'][1];
$search = $_SERVER['argv'][2];
if ($_SERVER['argc'] > 3)
	$stop = $_SERVER['argv'][3] == 1;
else	$stop = true;

/* get the absolute path and ensure it has a trailing slash */
$path = realpath($path);
if (substr($path, -1) !== DIRECTORY_SEPARATOR)
	$path .= DIRECTORY_SEPARATOR;

$queue = array($path => 1);
$done  = array();
$index = 0;
while(!empty($queue)) {
	/* get one element from the queue */
	foreach($queue as $path => $unused) {
		unset($queue[$path]);
		$done[$path] = null;
		break;
	}
	unset($unused);

	$dh = @opendir($path);
	if (!$dh) continue;
	while(($filename = readdir($dh)) !== false) {
		/* dont recurse back up levels */
		if ($filename == '.' || $filename == '..')
			continue;

		/* check if the filename matches the search term */
		if ($filename == $search) {
			echo "$path$filename\n";
			if ($stop)
				break 2;
		}

		/* get the full path */
		$filename = $path . $filename;

		/* resolve symlinks to their real path */
		if (is_link($filename))
			$filename = realpath($filename);

		/* queue directories for later search */
		if (is_dir($filename)) {
			/* ensure the path has a trailing slash */
			if (substr($filename, -1) !== DIRECTORY_SEPARATOR)
				$filename .= DIRECTORY_SEPARATOR;

			/* check if we have already queued this path, or have done it */
			if (array_key_exists($filename, $queue) || array_key_exists($filename, $done))
				continue;

			/* queue the file */
			$queue[$filename] = null;
		}
	}
	closedir($dh);
}</syntaxhighlight>

=={{header|PicoLisp}}==
<syntaxhighlight lang="picolisp">(let Dir "."
   (recur (Dir)
      (for F (dir Dir)
         (let Path (pack Dir "/" F)
            (cond
               ((=T (car (info Path)))             # Is a subdirectory?
                  (recurse Path) )                 # Yes: Recurse
               ((match '`(chop "s@.l") (chop F))   # Matches 's*.l'?
                  (println Path) ) ) ) ) ) )       # Yes: Print it</syntaxhighlight>
{{out}}
<pre>"./src64/sym.l"
"./src64/subr.l"
...</pre>

=={{header|Pop11}}==
Built-in procedure <code>sys_file_match</code> searches directories or directory trees using shell-like patterns (three dots indicate search for subdirectory tree).
<syntaxhighlight lang="pop11">lvars repp, fil;
;;; create path repeater
sys_file_match('.../*.p', '', false, 0) -> repp;
;;; iterate over paths
while (repp() ->> fil) /= termin do
     ;;; print the path
     printf(fil, '%s\n');
endwhile;</syntaxhighlight>

=={{header|PowerShell}}==
In PowerShell the <code>Get-ChildItem</code> cmdlet allows for recursive filtering on file names with simple wildcards:
<syntaxhighlight lang="powershell">Get-ChildItem -Recurse -Include *.mp3</syntaxhighlight>
For more complex filtering criteria the result of <code>Get-ChildItem</code> can be piped into the <code>Where-Object</code> cmdlet:
<syntaxhighlight lang="powershell">Get-ChildItem -Recurse |
  Where-Object { $_.Name -match 'foo[0-9]' -and $_.Length -gt 5MB }</syntaxhighlight>
To perform an action on every matching file the results can be piped into the <code>ForEach-Object</code> cmdlet:
<syntaxhighlight lang="powershell">Get-ChildItem -Recurse |
  Where-Object { $_.Name -match 'foo[0-9]' } |
  ForEach-Object { ... }</syntaxhighlight>
''Note:'' To include only ''files'' instead of directories too each of the above needs an additional<code>Where-Object</code> filter:
<syntaxhighlight lang="powershell">| Where-Object { !$_.PSIsContainer }</syntaxhighlight>


=={{header|Prolog}}==
{{works with|Swi-Prolog|8.3}}
<syntaxhighlight lang="prolog">
% submitted by Aykayayciti (Earl Lamont Montgomery)
% altered from fsaenzperez April 2019 
% (swi-prolog.discourse-group)
test_run :-
        proc_dir('C:\\vvvv\\vvvv_beta_39_x64').

proc_dir(Directory) :-
    format('Directory: ~w~n',[Directory]),
    directory_files(Directory,Files),!,  %cut inserted
    proc_files(Directory,Files).

proc_files(Directory, [File|Files]) :-
    proc_file(Directory, File),!, %cut inserted
    proc_files(Directory, Files).
proc_files(_Directory, []).

proc_file(Directory, File) :-
    (
        File = '.',
        directory_file_path(Directory, File, Path),
        exists_directory(Path),!,%cut inserted
        format('Directory: ~w~n',[File])
    ;
        File = '..',
        directory_file_path(Directory, File, Path),
        exists_directory(Path),!,%cut inserted
        format('Directory: ~w~n',[File])
    ;
        directory_file_path(Directory, File, Path),
        exists_directory(Path),!,%cut inserted
        proc_dir(Path)
    ;
        directory_file_path(Directory, File, Path),
        exists_file(Path),!,%cut inserted
        format('File: ~w~n',[File])
    ;
        format('Unknown: ~w~n',[File])
    ).</syntaxhighlight>

output :
<syntaxhighlight lang="prolog">?- test_run.
File: GMFBridge.ax
File: libeay32.dll
File: ssleay32.dll
File: license.txt
Directory: C:\vvvv\vvvv_beta_39_x64/licenses
Directory: .
Directory: ..
File: Apache.txt
File: BSD.txt
File: LGPL.txt
File: MIT.txt
File: MPL.txt
File: MS-PL-Eula.rtf
File: MS-PL.txt
File: MSR-SSLA.txt
</syntaxhighlight>





=={{header|PureBasic}}==
<syntaxhighlight lang="purebasic">Procedure.s WalkRecursive(dir,path.s,Pattern.s="\.txt$")
  Static RegularExpression 
  If Not RegularExpression
    RegularExpression=CreateRegularExpression(#PB_Any,Pattern)
  EndIf
  
  While NextDirectoryEntry(dir)
    If DirectoryEntryType(dir)=#PB_DirectoryEntry_Directory
      If DirectoryEntryName(dir)<>"." And DirectoryEntryName(dir)<>".."
        If ExamineDirectory(dir+1,path+DirectoryEntryName(dir),"")
          WalkRecursive(dir+1,path+DirectoryEntryName(dir)+"\",Pattern)
          FinishDirectory(dir+1)
        Else
          Debug "Error in "+path+DirectoryEntryName(dir)
        EndIf
      EndIf
    Else ; e.g. #PB_DirectoryEntry_File 
      If MatchRegularExpression(RegularExpression,DirectoryEntryName(dir))
        Debug DirectoryEntryName(dir)
      EndIf
    EndIf
  Wend
EndProcedure</syntaxhighlight>
<syntaxhighlight lang="purebasic">;- Implementation; Find all .log-files in the C:\Windows tree
ExamineDirectory(1,"C:\WINDOWS\","")
WalkRecursive(1,"C:\WINDOWS\","\.log$")
FinishDirectory(1)</syntaxhighlight>




=={{header|Prolog}}==
{{works with|Swi-Prolog|8.3}}
<syntaxhighlight lang="prolog">% submitted by Aykayayciti (Earl Lamont Montgomery)
% altered from fsaenzperez April 2019 
% (swi-prolog.discourse-group)
test_run :-
        proc_dir('C:\\vvvv\\vvvv_beta_39_x64').


proc_dir(Directory) :-
    format('Directory: ~w~n',[Directory]),
    directory_files(Directory,Files),!,  %cut inserted
    proc_files(Directory,Files).

proc_files(Directory, [File|Files]) :-
    proc_file(Directory, File),!, %cut inserted
    proc_files(Directory, Files).
proc_files(_Directory, []).

proc_file(Directory, File) :-
    (
        File = '.',
        directory_file_path(Directory, File, Path),
        exists_directory(Path),!,%cut inserted
        format('Directory: ~w~n',[File])
    ;
        File = '..',
        directory_file_path(Directory, File, Path),
        exists_directory(Path),!,%cut inserted
        format('Directory: ~w~n',[File])
    ;
        directory_file_path(Directory, File, Path),
        exists_directory(Path),!,%cut inserted
        proc_dir(Path)
    ;
        directory_file_path(Directory, File, Path),
        exists_file(Path),!,%cut inserted
        format('File: ~w~n',[File])
    ;
        format('Unknown: ~w~n',[File])
    ).</syntaxhighlight>

output :
<syntaxhighlight lang="prolog">?- test_run.
File: GMFBridge.ax
File: libeay32.dll
File: ssleay32.dll
File: license.txt
Directory: C:\vvvv\vvvv_beta_39_x64/licenses
Directory: .
Directory: ..
File: Apache.txt
File: BSD.txt
File: LGPL.txt
File: MIT.txt
File: MPL.txt
File: MS-PL-Eula.rtf
File: MS-PL.txt
File: MSR-SSLA.txt</syntaxhighlight>

=={{header|Python}}==
{{works with|Python|3.x}}
Use the standard [https://docs.python.org/3/library/pathlib.html#pathlib.Path.rglob pathlib.Path.rglob()] module to recursively walk a directory with optional filter.
<syntaxhighlight lang="python">
from pathlib import Path

for path in Path('.').rglob('*.*'):
    print(path)
</syntaxhighlight>

{{works with|Python|3.x}}
{{works with|Python|2.3+}}
This uses the standard [http://docs.python.org/py3k/library/os.html?highlight=os.walk#os.walk os.walk()] module function to walk a directory tree, and the [http://docs.python.org/py3k/library/fnmatch.html fnmatch] module for matching file names.
<syntaxhighlight lang="python">import fnmatch
import os

rootPath = '/'
pattern = '*.mp3'
 
for root, dirs, files in os.walk(rootPath):
    for filename in fnmatch.filter(files, pattern):
        print( os.path.join(root, filename))</syntaxhighlight>
{{works with|Python|<nowiki>2.x</nowiki>}}
{{works with|Python|<nowiki>3.x</nowiki>}}
A more strictly comparable port of this 2.3+ code to earlier versions of Python would be: 
<syntaxhighlight lang="python">from fnmatch import fnmatch
import os, os.path

def print_fnmatches(pattern, dir, files):
    for filename in files:
        if fnmatch(filename, pattern):
            print os.path.join(dir, filename)

os.path.walk('/', print_fnmatches, '*.mp3')</syntaxhighlight>
The old ''os.path.walk'' function was a challenge for many to use because of the need to pass a function into the walk, and any arguments to that function through to it ... as shown.  It's sometimes useful to pass mutable objects (lists, dictionaries, or instances of user-defined classes) to the inner function ... for example, to collect all the matching files for later processing.

Of course the function being passed down through ''os.path.walk()'' can also be an instance of an object which maintains it's own data collections.  Any matching criteria can be set as attributes of that object in advance and methods of that object can be called upon for later processing as well.  That would the an object oriented approach which would obviate the need for the "arguments" to be passed through ''os.path.walk()'' at all.
{{works with|Python|2.5}}
{{libheader|Path}}
(''Note:'' This uses a non-standard replacement to the '''os.path''' module)
<syntaxhighlight lang="python">from path import path

rootPath = '/'
pattern = '*.mp3'

d = path(rootPath)
for f in d.walkfiles(pattern):
  print f</syntaxhighlight>

=={{header|R}}==
<syntaxhighlight lang="r">dir("/bar/foo", "mp3",recursive=T)</syntaxhighlight>

=={{header|Racket}}==

<syntaxhighlight lang="racket">
-> (for ([f (in-directory "/tmp")] #:when (regexp-match? "\\.rkt$" f))
     (displayln f))
... *.rkt files including in nested directories ...
</syntaxhighlight>

=={{header|Raku}}==
(formerly Perl 6)

Using the [https://github.com/tadzik/File-Find/ File::Find] module:
<syntaxhighlight lang="raku" line>use File::Find;

.say for find dir => '.', name => /'.txt' $/;</syntaxhighlight>

Alternatively, a custom solution that provides the same interface as the built-in (non-recursive) <tt>dir</tt> function, and uses <tt>gather</tt>/<tt>take</tt> to return a lazy sequence:

<syntaxhighlight lang="raku" line>sub find-files ($dir, Mu :$test) {
    gather for dir $dir -> $path {
        if $path.basename ~~ $test { take $path }
        if $path.d                 { .take for find-files $path, :$test };
    }
}
 
.put for find-files '.', test => /'.txt' $/;</syntaxhighlight>

Or if you value performance over portability, here's a function that runs the GNU <tt>find</tt> program and returns a lazy sequence of the files it finds. Parameters are not subjected to shell expansion, and the null-byte (which cannot be present in file paths) is used as the path delimiter, so it should be pretty safe.

<syntaxhighlight lang="raku" line>sub find-files ($dir, :$pattern) {
    run('find', $dir, '-iname', $pattern, '-print0', :out, :nl«\0»).out.lines;
}

.say for find-files '.', pattern => '*.txt';</syntaxhighlight>

=={{header|Rascal}}==
<syntaxhighlight lang="rascal">//usage example: To list just Rascal source files,    Walk(|home:///workspace/|, ".rsc");  
module Walk
import String;
import IO;
public void Walk(loc a, str pattern){
	for (entry <- listEntries(a))
		if (endsWith(entry, pattern))
		 	println(entry);
		elseif (isDirectory(a+entry))
			Walk(a+entry, pattern);
}</syntaxhighlight>

=={{header|REALbasic}}==
<syntaxhighlight lang="vb">Sub printFiles(parentDir As FolderItem, pattern As String)
  For i As Integer = 1 To parentDir.Count
    If parentDir.Item(i).Directory Then
      printFiles(parentDir.Item(i), pattern)
    Else
      Dim rg as New RegEx
      Dim myMatch as RegExMatch
      rg.SearchPattern = pattern
      myMatch = rg.search(parentDir.Item(i).Name)
      If myMatch <> Nil Then Print(parentDir.Item(i).AbsolutePath)
    End If
  Next
End Sub</syntaxhighlight>
Accepts a FolderItem object and a Regex pattern as a string:
<syntaxhighlight lang="vb">
  Dim f As FolderItem = GetFolderItem("C:\Windows\system32")
  Dim pattern As String = "((?:[a-z][a-z]+))(\.)(dll)"  //all file names ending in .dll
  printFiles(f, pattern)</syntaxhighlight>

=={{header|Red}}==
<syntaxhighlight lang="red">Red []

walk: func [
    "Walk a directory tree recursively, setting WORD to each file and evaluating BODY."

    'word              "For each file, set with the absolute file path."
    directory [file!]  "Starting directory."
    body      [block!] "Block to evaluate for each file, during which WORD is set."
    /where
    rules [block!]     "Parse rules defining file names to include."
][
    foreach file read directory [
        if where [if not parse file rules [continue]]
        either dir? file: rejoin [directory file] [walk item file body] [
            set 'word file
            do body
        ]
    ]
]

rules: compose [
    any (charset [#"A" - #"Z"])
    ".TXT"
]

walk/where file %/home/user/ [print file] rules</syntaxhighlight>

=={{header|REXX}}==
===version 1===
{{works with|Regina}}
The following program was tested in a DOS window under Windows/XP and should work for all Microsoft Windows.
<syntaxhighlight lang="rexx">/*REXX program shows all files in a  directory tree  that match a given search criteria.*/
parse arg xdir;  if xdir=''  then xdir='\'       /*Any DIR specified?  Then use default.*/
@.=0                                             /*default result in case ADDRESS fails.*/
dirCmd= 'DIR /b /s'                              /*the DOS command to do heavy lifting. */
trace off                                        /*suppress REXX error message for fails*/
address system  dirCmd xdir  with output stem @. /*issue the DOS DIR command with option*/
if rc\==0  then do                               /*did the DOS DIR command get an error?*/
                say '***error!*** from DIR' xDIR /*error message that shows "que pasa". */
                say 'return code='  rc           /*show the  return code  from  DOS DIR.*/
                exit rc                          /*exit with    "     "     "    "   "  */
                end                              /* [↑]  bad ADDRESS cmd  (from DOS DIR)*/
#=@.rc                                           /*the number of  @.  entries generated.*/
if #==0  then #='   no   '                       /*use a better word choice for 0 (zero)*/
say center('directory '      xdir      " has "      #       ' matching entries.', 79, "─")

                do j=1  for #;       say @.j     /*show all the files that met criteria.*/
                end   /*j*/
exit @.0+rc                                      /*stick a fork in it,  we're all done. */</syntaxhighlight>
'''output''' &nbsp; when the following was used: &nbsp; <tt> I:\firefox*.exe </tt>
<pre>
─────────────directory  I:\firefox*.exe  has  6  matching entries.─────────────
I:\FIREFOX\firefox.exe
I:\FIREFOX\INSTALL\Firefox Setup 1.5.0.1.exe
I:\FIREFOX\INSTALL\Firefox Setup 2.0.0.4.exe
I:\FIREFOX\INSTALL\Firefox Setup 3.0.4.exe
I:\FIREFOX\INSTALL\Firefox Setup 3.6 Beta 5.exe
I:\FIREFOX\INSTALL\Firefox Setup 4.0 Beta 11.exe
</pre>

===version 2===
{{trans|BATCH-file}}
Works on Windows with ooRexx and Regina (not much REXX code in it)
<syntaxhighlight lang="rexx">'dir /s /b "%windir%\System32\*.exe"'</syntaxhighlight>

=={{header|Ring}}==
<syntaxhighlight lang="ring">
see "Testing DIR() " + nl
mylist = dir("C:\Ring")
for x in mylist
    if x[2]
       see "Directory : " + x[1] + nl
    else
       see "File : " + x[1] + nl
    ok
next
see "Files count : " + len(mylist)
</syntaxhighlight>
Output:
<pre>
Testing DIR()
Directory : bert
Directory : bin
Directory : calmosoft
Directory : doc
Directory : FlappyBird
Directory : gameengine
Directory : html
Directory : images
File : License.txt
File : music1.wav
File : ReadMe.txt
Directory : ring-master
Directory : samples
Directory : StarsFighter
File : start.bat
Directory : stdlib
Directory : SuperMan2016
File : unixdict.txt
Directory : weblib
Files count : 19
</pre>

=={{header|Ruby}}==

Using the Find core Module:

<syntaxhighlight lang="ruby">require 'find'

Find.find('/your/path') do |f|
   # print file and path to screen if filename ends in ".mp3"
   puts f if f.match(/\.mp3\Z/)
end</syntaxhighlight>

A little less verbose example using a shortcut for the glob method of Dir:

<syntaxhighlight lang="ruby">puts Dir['**/*.mp3']</syntaxhighlight>

=={{header|Rust}}==

Using std::fs::walk_dir (unstable as of Rust 1.1) with imperative for-loop:

<syntaxhighlight lang="rust">#![feature(fs_walk)]

use std::fs;
use std::path::Path;

fn main() {
    for f in fs::walk_dir(&Path::new("/home/pavel/Music")).unwrap() {
        let p = f.unwrap().path();
        if p.extension().unwrap_or("".as_ref()) == "mp3" {
            println!("{:?}", p);
        }
    }
}</syntaxhighlight>

=={{header|Scala}}==
This is not implemented in the Scala library. Here is a simple solution, building on [[Java]] class ''<code>java.io.File</code>'':

<syntaxhighlight lang="scala">import java.io.File

object `package` { 
  def walkTree(file: File): Iterable[File] = {
    val children = new Iterable[File] {
      def iterator = if (file.isDirectory) file.listFiles.iterator else Iterator.empty
    }
    Seq(file) ++: children.flatMap(walkTree(_))
  }
}

object Test extends App {
  val dir = new File("/home/user")
  for(f <- walkTree(dir)) println(f)
  for(f <- walkTree(dir) if f.getName.endsWith(".mp3")) println(f)
}</syntaxhighlight>

=={{header|Scheme}}==
Varies slightly depending on the implementation of scheme.
{{works with|Chicken Scheme}}
<syntaxhighlight lang="scheme">(use posix)
(use files)
(use srfi-13)

(define (walk FN PATH)
  (for-each (lambda (ENTRY) 
    (cond ((not (null? ENTRY))

	   (let ((MYPATH (make-pathname PATH ENTRY)))

	     (cond ((directory-exists? MYPATH)
		    (walk FN MYPATH) ))

	     (FN MYPATH) )))) (directory PATH #t) ))

(walk (lambda (X) (cond ((string-suffix? ".scm" X) (display X)(newline) ))) "/home/user/")</syntaxhighlight>
See also: '''(find-files ...)''' function in the '''posix''' module.
{{works with|Gauche}}
<syntaxhighlight lang="scheme">(use file.util)
(use srfi-13)

(define (walk FN PATH)
  (for-each (lambda (ENTRY) 
    (cond ((not (null? ENTRY))
	   (let ((MYPATH ENTRY))

	     (cond ((file-is-directory? MYPATH)
		    (walk FN MYPATH) ))
	     
	     (FN MYPATH) )))) (directory-list PATH :add-path? #t :children? #t ) ))

(walk (lambda (X) (cond ((string-suffix? ".scm" X) (display X)(newline) ))) "/home/user/")</syntaxhighlight>
See also: '''(find-file-in-paths ...)''' function in the '''file.util''' module.
{{works with|PLT Scheme}}
<syntaxhighlight lang="scheme">#lang scheme

(require srfi/13)

(define (walk FN PATH)
  (for-each (lambda (ENTRY) 
    (cond ((not (null? ENTRY))

	   (let ((MYPATH (build-path PATH ENTRY)))

	     (cond ((directory-exists? MYPATH)
		    (walk FN MYPATH) ))
	     
	     (FN MYPATH) )))) (directory-list PATH)))

(walk (lambda (X) (cond ((string-suffix? ".scm" (path->string X)) (display X)(newline) ))) "/home/user/")</syntaxhighlight>
See also: '''(find-files ...)''' function in the '''file''' module.
{{out|Sample output}}
<pre>
/home/user/one.scm
/home/user/lang/two.scm
[...]
</pre>

=={{header|Seed7}}==
Seed7 has a [http://seed7.sourceforge.net/manual/os.htm#Standard_path_representation standard path representation],
which is independent of the operating system. The function [http://seed7.sourceforge.net/manual/os.htm#readDir readDir]
reads the contents of a directory as array of strings. The files . and .. are left out, so it is not necessary to ignore them.
The function [http://seed7.sourceforge.net/manual/os.htm#fileType fileType] is used to determine, if a file is a directory.
The example below follows symbolic links. To ignore symbolic links use
[http://seed7.sourceforge.net/libraries/osfiles.htm#fileTypeSL%28in_string%29 fileTypeSL] instead of
[http://seed7.sourceforge.net/libraries/osfiles.htm#fileType%28in_string%29 fileType].

<syntaxhighlight lang="seed7">$ include "seed7_05.s7i";
  include "osfiles.s7i";

const proc: walkDir (in string: dirName, in string: extension) is func
  local
    var string: fileName is "";
    var string: path is "";
  begin
    for fileName range readDir(dirName) do
      path := dirName & "/" & fileName;
      if endsWith(path, extension) then
        writeln(path);
      end if;
      if fileType(path) = FILE_DIR then
        walkDir(path, extension);
      end if;
    end for;
  end func;

const proc: main is func
  begin
    walkDir(".", ".sd7");
  end func;</syntaxhighlight>

=={{header|Sidef}}==
<syntaxhighlight lang="ruby">func traverse(Block callback, Dir dir) {
    dir.open(\var dir_h) || return nil
 
    dir_h.entries.each { |entry|
        if (entry.is_a(Dir)) {
            traverse(callback, entry)
        } else {
            callback(entry)
        }
    }
}
 
var dir = Dir.cwd
var pattern = /foo/   # display files that contain 'foo'
 
traverse(
    { |file|
        if (file.basename ~~ pattern) {
            say file
        }
    } => dir
)</syntaxhighlight>

=={{header|Smalltalk}}==
{{works with|GNU Smalltalk}}
<syntaxhighlight lang="smalltalk">Directory extend [
  wholeContent: aPattern do: twoBlock [ 
    self wholeContent: aPattern withLevel: 0 do: twoBlock.
  ]
  wholeContent: aPattern withLevel: l do: twoBlock [
    |cont|
    cont := (self contents) asSortedCollection.
    cont remove: '.'; remove: '..'.
    cont
    do: [ :n | |fn ps|
      ps := (Directory pathSeparator) asString.
      fn := (self name), ps, n. 
      ((File name: fn) isDirectory)
      ifTrue: [
        twoBlock value: (n, ps) value: l.
	(Directory name: fn) wholeContent: aPattern withLevel: (l+1) do: twoBlock.
      ]
      ifFalse: [
        ( n =~ aPattern )
        ifMatched: [ :m |
          twoBlock value: n value: l
        ]
      ]
    ]
  ]
].</syntaxhighlight>

<syntaxhighlight lang="smalltalk">|d|
d := Directory name: '.'.
d wholeContent: '\.st$' do: [ :f :l |
   0 to: l do: [ :i | (Character tab) display ].
   f displayNl
].</syntaxhighlight>

=={{header|Swift}}==
{{works with|Swift|3.0}}
<syntaxhighlight lang="swift">import Foundation

let fileSystem = FileManager.default
let rootPath = "/"

// Enumerate the directory tree (which likely recurses internally)...

if let fsTree = fileSystem.enumerator(atPath: rootPath) {
	
    while let fsNodeName = fsTree.nextObject() as? NSString {
				
        let fullPath = "\(rootPath)/\(fsNodeName)"
				
        var isDir: ObjCBool = false
        fileSystem.fileExists(atPath: fullPath, isDirectory: &isDir)
				
        if !isDir.boolValue && fsNodeName.pathExtension == "txt" {
            print(fsNodeName)
        }
    }
}</syntaxhighlight>

=={{header|Tcl}}==
{{works with|Tcl|8.5}}
<syntaxhighlight lang="tcl">
package require fileutil
proc walkin {path cmd} {
    set normalized [::fileutil::fullnormalize $path]
    set myname [lindex [info level 0] 0]
    set children [glob -nocomplain -directory $path -types hidden *]
    lappend children {*}[glob -nocomplain -directory $path *]
    foreach child $children[set children {}] {
        if {[file tail $child] in {. ..}} {
            continue
        }
        if {[file isdirectory $child]} {
            if {[file type $child] eq "link"} {
                set normalizedchild [fileutil::fullnormalize $child]
                if {[string first $normalized/ $normalizedchild] == 0} {
                    #symlink to a directory in $path.  Avoid cyclic traversal.
                    #Don't descend.
                } else {
                    $myname $child $cmd
                }
            }
        }
        {*}$cmd $child
    }
}

walkin /home/usr {apply {fname {
    set tail [file tail $fname]
    if {[string match *.mp3 $tail]} {
        puts $fname
    }
}}} 
</syntaxhighlight>

=={{header|TXR}}==
There is more than one way to do this in TXR. A recursive walk could be coded using <code>open-directory</code> and <code>getline</code>. Or FFI could be used to gain access to some platform-specific functions like Microsoft's <code>FindFirstFile</code> and so forth.

===Using <code>ftw</code>===
TXR wraps and exposes the POSIX <code>nftw</code> function, which is demonstrated here. This function encapsulates a tree walk, and uses callbacks to inform the program of visited filesystem tree nodes, and of error situations. We can use a <code>lambda</code> for the code walk, or wrap the invocation of <code>ftw</code> with a macro which hides the <code>lambda</code> syntax.


Here we use the <code>build</code> macro for procedural list building to gather all of the found paths into a list, which is implicitly returned. The callback is an explicit <code>lambda</code>:

<syntaxhighlight lang="txrlisp">(build (ftw "." (lambda (path type stat level base)
                  (if (ends-with ".tl" path)
                    (add path)))))</syntaxhighlight>

{{out}}

<syntaxhighlight lang="txrlisp">("./tests/016/arith.tl" "./tests/014/dgram-stream.tl" "./tests/014/socket-basic.tl"
 "./tests/sock-common.tl" "./tests/012/ifa.tl" "./tests/012/except.tl"
 "./tests/012/fini.tl" "./tests/012/oop.tl" "./tests/012/circ.tl"
 "./tests/012/cont.tl" "./tests/012/aseq.tl" "./tests/012/quasi.tl"
 "./tests/012/struct.tl" "./tests/012/man-or-boy.tl" "./tests/017/glob-carray.tl"
 "./tests/017/glob-zarray.tl" "./tests/017/realpath.tl" "./tests/017/qsort.tl"
 "./tests/015/split.tl" "./tests/013/maze.tl" "./tests/common.tl"
 "./tests/011/special-1.tl" "./share/txr/stdlib/ifa.tl" "./share/txr/stdlib/with-stream.tl"
 "./share/txr/stdlib/pmac.tl" "./share/txr/stdlib/except.tl" "./share/txr/stdlib/awk.tl"
 "./share/txr/stdlib/package.tl" "./share/txr/stdlib/place.tl"
 "./share/txr/stdlib/trace.tl" "./share/txr/stdlib/type.tl" "./share/txr/stdlib/keyparams.tl"
 "./share/txr/stdlib/ffi.tl" "./share/txr/stdlib/ver.tl" "./share/txr/stdlib/build.tl"
 "./share/txr/stdlib/cadr.tl" "./share/txr/stdlib/hash.tl" "./share/txr/stdlib/error.tl"
 "./share/txr/stdlib/txr-case.tl" "./share/txr/stdlib/tagbody.tl"
 "./share/txr/stdlib/getopts.tl" "./share/txr/stdlib/socket.tl"
 "./share/txr/stdlib/struct.tl" "./share/txr/stdlib/getput.tl"
 "./share/txr/stdlib/path-test.tl" "./share/txr/stdlib/with-resources.tl"
 "./share/txr/stdlib/yield.tl" "./share/txr/stdlib/conv.tl" "./share/txr/stdlib/termios.tl")</syntaxhighlight>

For a regex pattern we can replace <code>(endswith ".tl" path)</code> with something like <code>(m$ path #/\.tl/)</code>.

TXR also provides the <code>fnmatch</code> function which can be used to match using a file globbing pattern.

<pre>1< (fnmatch "*.tl" "foo.tl")
t
2>< (fnmatch "*.tl" "foo.c")
nil</pre>

The <code>type</code>, <code>stat</code>, <code>level</code> and <code>base</code> callback arguments we are ignoring closely follow those of the POSIX C <code>nftw</code> function. <code>type</code> is a type code which indicates the kind of item visited: file, directory; <code>stat</code> is a Lisp version of <code>struct stat</code>, providing various information about the filesystem object: permissions, timestamps, inode number, etc.

A nice approach would be to capture a continuation in the callback, and then obtain the walk elements lazily; alas, capturing a continuation from a C library function's callback is not permitted, because the capture would span foreign stack frames.

===Using <code>glob*</code>===

TXR has a <code>glob*</code> function which, like <code>glob</code> is built on the POSIX C library function. <code>glob*</code> also provides Bash-style brace expansion, as well as the double star pattern, which we can use to find files recursively:

<syntaxhighlight lang="txrlisp">(glob* "**/*.c")</syntaxhighlight>

{{out}}

<syntaxhighlight lang="txrlisp">("args.c" "arith.c" "autoload.c" "buf.c" "cadr.c" "chksum.c" "chksums/crc32.c"
 "chksums/md5.c" "chksums/sha1.c" "chksums/sha256.c" "combi.c"
 "debug.c" "eval.c" "ffi.c" "filter.c" "ftw.c" "gc.c" "glob.c"
 "gzio.c" "hash.c" "itypes.c" "lib.c" "linenoise/example.c" "linenoise/linenoise.c"
 "match.c" "mpi/mpi.c" "mpi/mplogic.c" "parser.c" "protsym.c"
 "psquare.c" "rand.c" "regex.c" "signal.c" "socket.c" "stream.c"
 "struct.c" "strudel.c" "sysif.c" "syslog.c" "termios.c" "time.c"
 "tree.c" "txr.c" "unwind.c" "utf8.c" "vm.c")</syntaxhighlight>

=={{header|UNIX Shell}}==
{{works with|Bourne Again SHell}}
The "find" command gives a one-line solution for simple patterns:
<syntaxhighlight lang="bash">find . -name '*.txt' -type f </syntaxhighlight>
"find" can also be used to find files matching more complex patterns as illustrated in the section on [[#UnixPipes|Unix Pipes]] below.

Using "bash" version 4 or later, you can use "globstar" or "dotglob", depending on whether you want hidden directories to be searched:
<syntaxhighlight lang="bash">#! /bin/bash
# Warning: globstar excludes hidden directories.
# Turn on recursive globbing (in this script) or exit if the option is not supported:
shopt -s globstar || exit

for f in **
do
  if [[ "$f" =~ \.txt$ ]] ; then
    echo "$f"
  fi
done</syntaxhighlight>
Here is a solution that does not use "find".
<syntaxhighlight lang="bash">#! /bin/bash

indent_print()
{
    for((i=0; i < $1; i++)); do
	echo -ne "\t"
    done
    echo "$2"
}

walk_tree()
{
    local oldifs bn lev pr pmat
    if [[ $# -lt 3 ]]; then
	if [[ $# -lt 2 ]]; then
	    pmat=".*"
	else
	    pmat="$2"
	fi
	walk_tree "$1" "$pmat" 0
	return
    fi
    lev=$3
    [ -d "$1" ] || return
    oldifs=$IFS
    IFS="
"
    for el in $1/*; do
	bn=$(basename "$el")
	if [[ -d "$el" ]]; then
	    indent_print $lev "$bn/"
	    pr=$( walk_tree "$el" "$2" $(( lev + 1)) )
	    echo "$pr"
	else
	    if [[ "$bn" =~ $2 ]]; then
		indent_print $lev "$bn"
	    fi
	fi
    done
    IFS=$oldifs
}

walk_tree "$1" "\.sh$"</syntaxhighlight>
A simplified version that gives the same output:
<syntaxhighlight lang="bash">#! /usr/bin/env bash
  
walk_tree() {
	ls "$1" | while IFS= read i; do
		if [ -d "$1/$i" ]; then
			echo "$i/"
			walk_tree "$1/$i" "$2" | sed -r 's/^/\t/'
		else
			echo "$i" | grep -E "$2"
		fi
	done
}
 
walk_tree "$1" "\.sh$"</syntaxhighlight>

=={{header|UnixPipes}}==
As illustrated [[#UNIX Shell|above]], the "find" command can be used with the -name option to match simple patterns.  To find files matching more complex patterns, the results of "find" can be piped, e.g.
<syntaxhighlight lang="bash">find . -type f | egrep '\.txt$|\.TXT$'</syntaxhighlight>
One way to run a command against each file that is found is to use "xargs", but if there is any possibility that a filename contains a space or tab character, then the following model should be used:
<syntaxhighlight lang="bash"> find . -type f -name "*.txt" -print0 | xargs -0 fgrep sometext</syntaxhighlight>

=={{header|Visual Basic .NET}}==
{{works with|Visual Basic .NET|9.0+}}
This uses the OS pattern matching
<syntaxhighlight lang="vbnet">Sub walkTree(ByVal directory As IO.DirectoryInfo, ByVal pattern As String)
    For Each file In directory.GetFiles(pattern)
        Console.WriteLine(file.FullName)
    Next
    For Each subDir In directory.GetDirectories
        walkTree(subDir, pattern)
    Next
End Sub</syntaxhighlight>

=={{header|Wren}}==
{{libheader|Wren-pattern}}
{{libheader|Wren-sort}}
<syntaxhighlight lang="wren">import "io" for Directory, File
import "./pattern" for Pattern
import "./sort" for Sort

var walk // recursive function
walk = Fn.new { |dir, pattern, found|
    if (!Directory.exists(dir)) Fiber.abort("Directory %(dir) does not exist.")
    var files = Directory.list(dir)
    for (f in files) {
        var path = dir + "/%(f)"
        if (File.exists(path)) {  // it's a file not a directory
            if (pattern.isMatch(f)) found.add(f)
        } else {
            walk.call(path, pattern, found)
        }
    }
}

// get all C header files beginning with 'va' or 'vf'
var p = Pattern.new("v[a|f]+0^..h", Pattern.whole)
var found = []
walk.call("/usr/include", p, found)
Sort.quick(found)
for (f in found) System.print(f)</syntaxhighlight>

{{out}}
<pre>
valarray_after.h
valarray_array.h
valarray_before.h
valgrind.h
validate.h
values.h
vfio.h
vfio_ccw.h
vfs.h
</pre>

=={{header|zkl}}==
<syntaxhighlight lang="zkl">d:=File.globular("..","s*.zkl")</syntaxhighlight>
Lots of options, here I'm using the defaults: recurse, just file matches (not directory names) and return a bit bucket of ASCIIZ strings.
{{out}}
<pre>
d.pump(Console.println)
../Tmp/sieve.zkl
../Tmp/sock2.zkl
../Tmp/strands.zkl
../Tmp/sd.zkl
../Src/startup.zkl
../Src/ZenKinetic/sieve.zkl
../Tests/subscript.zkl
../Tests/Object/socket.zkl
../Tests/Object/string.zkl
</pre>
globular will write to a object that has a write method or just call a method or function, which is nice for sending data to other threads (eg multi-threaded find/grep). To do the above example in one shot (without saving the results):
<syntaxhighlight lang="zkl">File.globular("..","s*.zkl",True,0,Console.println)</syntaxhighlight>

=={{header|Zsh}}==
Zsh has recursive globbing. The GLOB_DOTS option allows files beginning with a period to be matched.
<syntaxhighlight lang="zsh">setopt GLOB_DOTS
print -l -- **/*.txt</syntaxhighlight>
GLOB_DOTS can be set temporarily with the 'D' modifier.
<syntaxhighlight lang="zsh">print -l -- **/*.txt(D)</syntaxhighlight>

{{omit from|ACL2|Very limited filesystem support.}}
{{omit from|Befunge}} <!-- No filesystem support -->
{{omit from|M4}}
{{omit from|MUMPS|Maybe it could be done. But not with $ZF unless you wrote a OS level script and called that}}
{{omit from|PARI/GP}}
{{omit from|Retro}}
{{omit from|TI-83 BASIC}} {{omit from|TI-89 BASIC}} <!-- Does not have a filesystem, just namespaced variables, which can't be listed from a program. -->
{{omit from|Unlambda|Does not have file system support.}}
{{omit from|ZX Spectrum Basic|Does not have subdirectories}}
{{omit from|Axe}}