Walk a directory/Recursively
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. 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
- Walk a directory/Non-recursively (read a single directory).
8th
<lang forth> "*.c" f:rglob \ top of stack now has list of all "*.c" files, recursively </lang>
Ada
<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;</lang> 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.
ALGOL 68
<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$";
PROC match sort a68 and print = (STRING path file)VOID:
IF grep in string(re sort a68, path file, NIL, NIL) = match THEN print((path file, new line)) FI;
walk tree(".", match sort a68 and print)</lang>
- Sample output:
./Shell_sort_c.a68 ./Quick_sort.a68 ./Shell_sort.a68 ./Cocktail_Sort.a68 ./Selection_Sort.a68 ./Merge_sort.a68 ./tmp/test_sort.a68 ./Bobosort.a68 ./Sorting_an_Array_of_Integers.a68 ./Insertion_Sort.a68 ./Permutation_Sort.a68
AutoHotkey
Display all TMP files in Temp directory and its subdirectories. <lang autohotkey>Loop, %A_Temp%\*.tmp,,1
out .= A_LoopFileName "`n"
MsgBox,% out</lang>
BaCon
This line will recursively walk though all directories starting from the current directory ".": <lang qbasic>PRINT WALK$(".", 1, ".+", TRUE, NL$)</lang>
Batch File
A sample code that displays all the EXE files in System32 directory recursively. <lang dos>dir /s /b "%windir%\System32\*.exe"</lang>
If you wanted to apply some command to each item in a directory tree, then use FOR with the switch /R. For example, to apply the ECHO command to every DLL file in C:\Windows\System32:
<lang dos>FOR /R C:\Windows\System32 %%F IN (*.DLL) DO ECHO "%%F"</lang> This can be done from outside a batch file (entered directly at the command prompt) by changing the double percent signs (%%) to single percents (%): <lang dos>FOR /R C:\Windows\System32 %F IN (*.DLL) DO ECHO "%F"</lang>
BBC BASIC
<lang bbcbasic> directory$ = "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$)
ENDIF
SYS "FindNextFile", sh%, dir% TO res%
UNTIL res% = 0
SYS "FindClose", sh%
ENDIF
ENDPROC</lang>
C
<lang C>#include <sys/types.h>
- include <sys/stat.h>
- include <unistd.h>
- include <dirent.h>
- include <regex.h>
- include <stdio.h>
- include <string.h>
- include <errno.h>
- include <err.h>
enum { WALK_OK = 0, WALK_BADPATTERN, WALK_NAMETOOLONG, WALK_BADIO, };
- define WS_NONE 0
- define WS_RECURSIVE (1 << 0)
- define WS_DEFAULT WS_RECURSIVE
- define WS_FOLLOWLINK (1 << 1) /* follow symlinks */
- define WS_DOTFILES (1 << 2) /* per unix convention, .file is hidden */
- define WS_MATCHDIRS (1 << 3) /* if pattern is used on dir names too */
int walk_recur(char *dname, regex_t *reg, int spec) { struct dirent *dent; DIR *dir; struct stat st; char fn[FILENAME_MAX]; int res = WALK_OK; int len = strlen(dname); if (len >= FILENAME_MAX - 1) return WALK_NAMETOOLONG;
strcpy(fn, dname); fn[len++] = '/';
if (!(dir = opendir(dname))) { warn("can't open %s", dname); return WALK_BADIO; }
errno = 0; while ((dent = readdir(dir))) { if (!(spec & WS_DOTFILES) && dent->d_name[0] == '.') continue; if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, "..")) continue;
strncpy(fn + len, dent->d_name, FILENAME_MAX - len); if (lstat(fn, &st) == -1) { warn("Can't stat %s", fn); res = WALK_BADIO; continue; }
/* don't follow symlink unless told so */ if (S_ISLNK(st.st_mode) && !(spec & WS_FOLLOWLINK)) continue;
/* will be false for symlinked dirs */ if (S_ISDIR(st.st_mode)) { /* recursively follow dirs */ if ((spec & WS_RECURSIVE)) walk_recur(fn, reg, spec);
if (!(spec & WS_MATCHDIRS)) continue; }
/* pattern match */ if (!regexec(reg, fn, 0, 0, 0)) puts(fn); }
if (dir) closedir(dir); return res ? res : errno ? WALK_BADIO : WALK_OK; }
int walk_dir(char *dname, char *pattern, int spec) { regex_t r; int res; if (regcomp(&r, pattern, REG_EXTENDED | REG_NOSUB)) return WALK_BADPATTERN; res = walk_recur(dname, &r, spec); regfree(&r);
return res; }
int main() { int r = walk_dir(".", ".\\.c$", 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; }</lang>
With the 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.
<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; }</lang>
Windows
<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; }</lang>
C#
<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.");
}
}
} </lang>
C++
<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";
}
}</lang>
<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;
}
}</lang>
Caché ObjectScript
<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 }
} </lang>
- Example:
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
Clojure
The standard function file-seq does a tree walk. <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")) </lang>
CoffeeScript
<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</lang>
Common Lisp
This example uses the CL-FAD 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 :depth-first-p nil is passed.
<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))))
</lang>
<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 [...]</lang>
D
<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;
}</lang>
E
<lang e>def walkTree(directory, pattern) {
for name => file in directory {
if (name =~ rx`.*$pattern.*`) {
println(file.getPath())
}
if (file.isDirectory()) {
walkTree(file, pattern)
}
}
}</lang>
- Example:
<lang e>? walkTree(<file:/usr/share/man>, "rmdir") /usr/share/man/man1/rmdir.1 /usr/share/man/man2/rmdir.2</lang>
Elixir
<lang elixir>defmodule Walk_directory do
def recursive(dir \\ ".") do
Enum.each(File.ls!(dir), fn file ->
IO.puts fname = "#{dir}/#{file}"
if File.dir?(fname), do: recursive(fname)
end)
end
end
Walk_directory.recursive</lang>
- Output:
./check.exs ./e.bat ./foo ./foo/bar ./foo/bar/1 ./foo/bar/2 ./foo/bar/a ./foo/bar/b ./input.txt ./test.beam ./test.exs ./test.txt
Emacs Lisp
<lang lisp>ELISP> (directory-files-recursively "/tmp/el" "\\.el$") ("/tmp/el/1/c.el" "/tmp/el/a.el" "/tmp/el/b.el")</lang>
Erlang
Use builtin function filelib:fold_files/5
- Output:
10> filelib:fold_files( "/tmp", ".*", true, fun(File, Acc) -> [File|Acc] end, []). ["/tmp/clearcase_inst/local.conf", "/tmp/.X0-lock","/tmp/.cron-check-4000-was-here", "/tmp/kerneloops.XyN0SP","/tmp/npicagwD7tf"] 11> filelib:fold_files( "/tmp", ".*\.conf", true, fun(File, Acc) -> [File|Acc] end, []). ["/tmp/clearcase_inst/local.conf"]
F#
This code is tail-recursive and lazy. <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")</lang>
Factor
<lang factor>USE: io.directories.search
"." t [
dup ".factor" tail? [ print ] [ drop ] if
] each-file</lang>
Forth
<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 </lang>
Gambas
Click this link to run this code <lang gambas>Public Sub Main() Dim sTemp As String
For Each sTemp In RDir("/etc", "*.d")
Print sTemp
Next
End</lang> Output:
sysctl.d systemd/ntp-units.d pam.d security/limits.d security/namespace.d insserv.conf.d udev/hwdb.d ....
GAP
<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);</lang>
Go
<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)
}</lang>
Groovy
Search text files in current directory tree in a depth-first fashion:
<lang groovy>new File('.').eachFileRecurse {
if (it.name =~ /.*\.txt/) println it;
}</lang>
Shorter variant: <lang groovy>new File('.').eachFileRecurse ~/.*\.txt/, { println it }</lang>
Variant processing only files: <lang groovy>new File('.').eachFileRecurse FILES, ~/.*\.txt/, { println it }</lang>
Flexible search, traversal can be adapted by providing various options in the options Map, see documentation of method: traverse(Map options, Closure closure) <lang groovy>new File('.').traverse(
type : FILES,
nameFilter : ~/.*\.txt/,
preDir : { if (it.name == '.svn') return SKIP_SUBTREE },
) { println it } </lang>
GUISS
Here we list all files that match the pattern m*.txt in "My Documents" and all of its subfolders: <lang guiss>Start,Find,Files and Folders,Dropdown: Look in>My Documents, Inputbox: filename>m*.txt,Button:Search</lang>
Haskell
Using the packages directory and filemanip
<lang haskell>import System.Environment import System.Directory import System.FilePath.Find
search pat dir =
find always (fileName ~~? pat) dir
main = do [pat] <- getArgs
dir <- getCurrentDirectory
files <- search pat dir
mapM_ putStrLn files</lang>
or more classic way: <lang haskell>import System.FilePath.Posix import System.Directory import System.IO
dir_walk :: FilePath -> (FilePath -> IO ()) -> IO () dir_walk top filefunc = do
isDirectory <- doesDirectoryExist top
if isDirectory
then
do
files <- listDirectory top
mapM_ (\file -> dir_walk (top </> file) filefunc) files
else
filefunc top
main :: IO () main = do
hSetEncoding stdout utf8
hSetEncoding stdin utf8
let worker fname =
do if (takeExtension fname == ".hs")
then putStrLn fname
else return ()
dir_walk "." worker</lang>
Icon and Unicon
Icon
Icon doesn't support 'stat' or 'open' of a directory; however, information can be obtained by use of the system function to access command line.
Unicon
<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</lang>
IDL
<lang idl>result = file_search( directory, '*.txt', count=cc )</lang> This will descend down the directory/ies in the variable "directory" (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 "cc"
J
<lang j>require 'dir' >{."1 dirtree '*.html'</lang>
The verb dirtree returns a file listing of a directory tree as a boxed matrix with file names in the first column. The primitives >{."1 will return the unboxed contents of the first column.
'*.html' can be replaced by another pattern, of course.
Java
Done using no pattern. But with end string comparison which gave better results. <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());
}
}
}
}
}
}</lang>
Luckily, java.nio.file.Files gives us a walkFileTree method that does exactly what this task calls for.
<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; } }); } }</lang>
<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 ); } } </lang>
JavaScript
<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$');</lang>
Julia
<lang julia>rootpath = "/home/user/music" pattern = r".mp3$"
for (root, dirs, files) in walkdir(rootpath)
for file in files
if occursin(pattern, file) println(file) end
end
end</lang>
Kotlin
<lang scala>// version 1.2.0
import java.io.File
fun walkDirectoryRecursively(dirPath: String, pattern: Regex): Sequence<String> {
val d = File(dirPath)
require (d.exists() && d.isDirectory())
return d.walk().map { it.name }.filter { it.matches(pattern) }.sorted().distinct() }
fun main(args: Array<String>) {
val r = Regex("""^v(a|f).*\.h$""") // get all C header files beginning with 'va' or 'vf'
val files = walkDirectoryRecursively("/usr/include", r)
for (file in files) println(file)
} </lang>
Output (Ubuntu 14.04):
valarray_after.h valarray_array.h valarray_before.h values.h vfio.h vfs.h
Lasso
<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</lang>
-> array(myfile.lasso, test.lasso, rosetta.lasso)
LiveCode
<lang LiveCode>function recurDir dir, ext
set the defaultFolder to dir
repeat for each line fi in the files
if fileExt(fi) = ext then
put the longfilepath of fi & cr after fileList
end if
end repeat
repeat for each line di in the folders
if di is not "." and di is not ".." then
put recurDir((dir & slash & di), ext) & cr after fileList
end if
end repeat
filter fileList without empty
return fileList
end recurDir
function fileExt f
set the itemdel to "." return the last item of f
end fileExt</lang> Example <lang LiveCode>put recurDir(the home folder & slash & "music", "mp3")</lang> Output
... /Users/xxx/music/albumx/trackx.mp3 /Users/xxx/music/albumx/trackx2.mp3 /Users/xxx/music/albumy/tracky.mp3 ...
Lua
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. <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</lang>
Mathematica
The built-in function FileNames does exactly this:
FileNames[]lists all files in the current working directory.FileNames[form]lists all files in the current working directory whose names match the string pattern form.FileNames[{form1,form2,...}]lists all files whose names match any of the form_i.FileNames[forms,{dir1,dir2,...}]lists files with names matching forms in any of the directories dir_i.FileNames[forms,dirs,n]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): <lang Mathematica>FileNames["*"] FileNames["*.png", $RootDirectory] FileNames["*", {"*"}, Infinity]</lang> the result can be printed with Print /@ FileNames[....]
MATLAB / Octave
<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; </lang>
MAXScript
<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"</lang>
Nim
<lang nim>import os, re
for file in walkDirRec "/":
if file.match re".*\.mp3": echo file</lang>
Objeck
<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();
};
};
};
}
}</lang>
Objective-C
<lang objc>NSString *dir = NSHomeDirectory(); NSDirectoryEnumerator *de = [[NSFileManager defaultManager] enumeratorAtPath:dir];
for (NSString *file in de)
if ([[file pathExtension] isEqualToString:@"mp3"]) NSLog(@"%@", file);</lang>
OCaml
<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;
- </lang>
ooRexx
version 1
<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</lang>
- Output:
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
version 2
Get only files matching the file-spec. <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 </lang>
- Output:
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
Oz
<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}</lang>
Perl
Use the File::Find module from CPAN:
<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;</lang>
Or if you need maximum performance and are on a 'nix system, open a pipe to the GNU find program:
<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');</lang>
Perl 6
Using the File::Find module: <lang perl6>use File::Find;
.say for find dir => '.', name => /'.txt' $/;</lang>
Alternatively, a custom solution that provides the same interface as the built-in (non-recursive) dir function, and uses gather/take to return a lazy sequence:
<lang perl6>sub find-files ($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' $/;</lang>
Or if you value performance over portability, here's a function that runs the GNU find program and returns a lazy sequence of the files it finds. Parameters are not subjected to shell expansion, and the null-byte (which cannot be present in file paths) is used as the path delimiter, so it should be pretty safe.
<lang perl6>sub find-files ($dir, :$pattern) {
run('find', $dir, '-iname', $pattern, '-print0', :out, :nl«\0»).out.lines;
}
.say for find-files '.', pattern => '*.txt';</lang>
Phix
There is a builtin routine for this, walk_dir() - if interested you can find the full implementation in builtins\file.e (an autoinclude). <lang Phix>function find_pfile(string pathname, sequence dirent)
if match("pfile.e",dirent[D_NAME]) then
-- return pathname&dirent[D_NAME] -- to terminate scan
?pathname&"\\"&dirent[D_NAME] end if return 0
end function
?walk_dir("C:\\Program Files (x86)\\Phix",routine_id("find_pfile"),1)</lang> Passing 1 as the third parameter makes it scan recursively.
- Output:
"C:\\Program Files (x86)\\Phix\\.hg\\store\\data\\builtins\\pfile.e.i" "C:\\Program Files (x86)\\Phix\\builtins\\pfile.e" 0
[the final 0 is from the walk_dir() call, whereas both paths are printed from inside find_pfile()]
PHP
<lang PHP>function findFiles($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 $file . "\n";
}
}
} findFiles('./foo', '/\.bar$/');</lang> This implementation uses Perl compatible regular expressions to match the whole path of the file
PHP BFS (Breadth First Search)
<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); }</lang>
PicoLisp
<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</lang>
- Output:
"./src64/sym.l" "./src64/subr.l" ...
Pop11
Built-in procedure sys_file_match searches directories or directory trees using shell-like patterns (three dots indicate search for subdirectory tree).
<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;</lang>
PowerShell
In PowerShell the Get-ChildItem cmdlet allows for recursive filtering on file names with simple wildcards:
<lang powershell>Get-ChildItem -Recurse -Include *.mp3</lang>
For more complex filtering criteria the result of Get-ChildItem can be piped into the Where-Object cmdlet:
<lang powershell>Get-ChildItem -Recurse |
Where-Object { $_.Name -match 'foo[0-9]' -and $_.Length -gt 5MB }</lang>
To perform an action on every matching file the results can be piped into the ForEach-Object cmdlet:
<lang powershell>Get-ChildItem -Recurse |
Where-Object { $_.Name -match 'foo[0-9]' } |
ForEach-Object { ... }</lang>
Note: To include only files instead of directories too each of the above needs an additionalWhere-Object filter:
<lang powershell>| Where-Object { !$_.PSIsContainer }</lang>
PureBasic
<lang PureBasic>Procedure.s WalkRecursive(dir,path.s,Pattern.s="\.txt$")
Static RegularExpression
If Not RegularExpression
RegularExpression=CreateRegularExpression(#PB_Any,Pattern)
EndIf
While NextDirectoryEntry(dir)
If DirectoryEntryType(dir)=#PB_DirectoryEntry_Directory
If DirectoryEntryName(dir)<>"." And DirectoryEntryName(dir)<>".."
If ExamineDirectory(dir+1,path+DirectoryEntryName(dir),"")
WalkRecursive(dir+1,path+DirectoryEntryName(dir)+"\",Pattern)
FinishDirectory(dir+1)
Else
Debug "Error in "+path+DirectoryEntryName(dir)
EndIf
EndIf
Else ; e.g. #PB_DirectoryEntry_File
If MatchRegularExpression(RegularExpression,DirectoryEntryName(dir))
Debug DirectoryEntryName(dir)
EndIf
EndIf
Wend
EndProcedure</lang> <lang PureBasic>;- Implementation; Find all .log-files in the C:\Windows tree ExamineDirectory(1,"C:\WINDOWS\","") WalkRecursive(1,"C:\WINDOWS\","\.log$") FinishDirectory(1)</lang>
Python
This uses the standard os.walk() module function to walk a directory tree, and the fnmatch module for matching file names. <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))</lang>
A more strictly comparable port of this 2.3+ code to earlier versions of Python would be: <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')</lang> 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.
(Note: This uses a non-standard replacement to the os.path module) <lang python>from path import path
rootPath = '/' pattern = '*.mp3'
d = path(rootPath) for f in d.walkfiles(pattern):
print f</lang>
R
<lang R>dir("/bar/foo", "mp3",recursive=T)</lang>
Racket
<lang Racket> -> (for ([f (in-directory "/tmp")] #:when (regexp-match? "\\.rkt$" f))
(displayln f))
... *.rkt files including in nested directories ... </lang>
Rascal
<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); }</lang>
REALbasic
<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</lang> Accepts a FolderItem object and a Regex pattern as a string: <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)</lang>
REXX
version 1
The following program was tested in a DOS window under Windows/XP and should work for all Microsoft Windows. <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. */</lang> output when the following was used: I:\firefox*.exe
─────────────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
version 2
Works on Windows with ooRexx and Regina (not much REXX code in it) <lang rexx>'dir /s /b "%windir%\System32\*.exe"'</lang>
Ring
<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) </lang> Output:
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
Ruby
Using the Find core Module:
<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</lang>
A little less verbose example using a shortcut for the glob method of Dir:
<lang ruby>puts Dir['**/*.mp3']</lang>
Rust
Using std::fs::walk_dir (unstable as of Rust 1.1) with imperative for-loop:
<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);
}
}
}</lang>
Scala
This is not implemented in the Scala library. Here is a simple solution, building on Java class java.io.File:
<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)
}</lang>
Scheme
Varies slightly depending on the implementation of scheme.
<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/")</lang> See also: (find-files ...) function in the posix module.
<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/")</lang> See also: (find-file-in-paths ...) function in the file.util module.
<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/")</lang> See also: (find-files ...) function in the file module.
- Sample output:
/home/user/one.scm /home/user/lang/two.scm [...]
Seed7
Seed7 has a standard path representation, which is independent of the operating system. The function 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 fileType is used to determine, if a file is a directory. The example below follows symbolic links. To ignore symbolic links use fileTypeSL instead of fileType.
<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;</lang>
Sidef
<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
)</lang>
Smalltalk
<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
]
]
]
]
].</lang>
<lang smalltalk>|d| d := Directory name: '.'. d wholeContent: '\.st$' do: [ :f :l |
0 to: l do: [ :i | (Character tab) display ]. f displayNl
].</lang>
Swift
<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)
}
}
}</lang>
Tcl
<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
}
}}} </lang>
TXR
There is more than one way to do this in TXR. A recursive walk could be coded using open-directory and getline. Or FFI could be used to gain access to some platform-specific functions like Microsoft's FindFirstFile and so forth.
TXR wraps and exposes the POSIX nftw 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 lambda for the code walk, or wrap the invocation of ftw with a macro which hides the lambda syntax.
Here we use the build macro for procedural list building to gather all of the found paths into a list, which is implicitly returned. The callback is an explicit lambda:
<lang txrlisp>(build (ftw "." (lambda (path type stat level base)
(if (ends-with ".tl" path)
(add path)))))</lang>
- Output:
<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")</lang>
For a regex pattern we can replace (endswith ".tl" path) with something like (m$ path #/\.tl/).
TXR also provides the fnmatch function which can be used to match using a file globbing pattern.
1< (fnmatch "*.tl" "foo.tl") t 2>< (fnmatch "*.tl" "foo.c") nil
The type, stat, level and base callback arguments we are ignoring closely follow those of the POSIX C nftw function. type is a type code which indicates the kind of item visited: file, directory; stat is a Lisp version of struct stat, 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.
UNIX Shell
The "find" command gives a one-line solution for simple patterns: <lang bash>find . -name '*.txt' -type f </lang> "find" can also be used to find files matching more complex patterns as illustrated in the section on 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: <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</lang> Here is a solution that does not use "find". <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 "$1" "\.sh$"</lang> A simplified version that gives the same output: <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 "$1" "\.sh$"</lang>
UnixPipes
As illustrated 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. <lang bash>find . -type f | egrep '\.txt$|\.TXT$'</lang> 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: <lang bash> find . -type f -name "*.txt" -print0 | xargs -0 fgrep sometext</lang>
Visual Basic .NET
This uses the OS pattern matching <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</lang>
zkl
<lang zkl>d:=File.globular("..","s*.zkl")</lang> Lots of options, here I'm using the defaults: recurse, just file matches (not directory names) and return a bit bucket of ASCIIZ strings.
- Output:
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
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): <lang zkl>File.globular("..","s*.zkl",True,0,Console.println)</lang>
Zsh
Zsh has recursive globbing. The GLOB_DOTS option allows files beginning with a period to be matched. <lang zsh>setopt GLOB_DOTS print -l -- **/*.txt</lang> GLOB_DOTS can be set temporarily with the 'D' modifier. <lang zsh>print -l -- **/*.txt(D)</lang>
- Programming Tasks
- File System Operations
- Recursion
- 8th
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- BBC BASIC
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- Axe/Omit