1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
|
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>File System Node.js v0.10.29 Manual & Documentation</title>
<link rel="stylesheet" href="assets/style.css">
<link rel="stylesheet" href="assets/sh.css">
<link rel="canonical" href="http://nodejs.org/api/fs.html">
</head>
<body class="alt apidoc" id="api-section-fs">
<div id="intro" class="interior">
<a href="/" title="Go back to the home page">
<img id="logo" src="http://nodejs.org/images/logo-light.png" alt="node.js">
</a>
</div>
<div id="content" class="clearfix">
<div id="column2" class="interior">
<ul>
<li><a href="/" class="home">Home</a></li>
<li><a href="/download/" class="download">Download</a></li>
<li><a href="/about/" class="about">About</a></li>
<li><a href="http://npmjs.org/" class="npm">npm Registry</a></li>
<li><a href="http://nodejs.org/api/" class="docs current">Docs</a></li>
<li><a href="http://blog.nodejs.org" class="blog">Blog</a></li>
<li><a href="/community/" class="community">Community</a></li>
<li><a href="/logos/" class="logos">Logos</a></li>
<li><a href="http://jobs.nodejs.org/" class="jobs">Jobs</a></li>
</ul>
<p class="twitter"><a href="http://twitter.com/nodejs">@nodejs</a></p>
</div>
<div id="column1" class="interior">
<header>
<h1>Node.js v0.10.29 Manual & Documentation</h1>
<div id="gtoc">
<p>
<a href="index.html" name="toc">Index</a> |
<a href="all.html">View on single page</a> |
<a href="fs.json">View as JSON</a>
</p>
</div>
<hr>
</header>
<div id="toc">
<h2>Table of Contents</h2>
<ul>
<li><a href="#fs_file_system">File System</a><ul>
<li><a href="#fs_fs_rename_oldpath_newpath_callback">fs.rename(oldPath, newPath, callback)</a></li>
<li><a href="#fs_fs_renamesync_oldpath_newpath">fs.renameSync(oldPath, newPath)</a></li>
<li><a href="#fs_fs_ftruncate_fd_len_callback">fs.ftruncate(fd, len, callback)</a></li>
<li><a href="#fs_fs_ftruncatesync_fd_len">fs.ftruncateSync(fd, len)</a></li>
<li><a href="#fs_fs_truncate_path_len_callback">fs.truncate(path, len, callback)</a></li>
<li><a href="#fs_fs_truncatesync_path_len">fs.truncateSync(path, len)</a></li>
<li><a href="#fs_fs_chown_path_uid_gid_callback">fs.chown(path, uid, gid, callback)</a></li>
<li><a href="#fs_fs_chownsync_path_uid_gid">fs.chownSync(path, uid, gid)</a></li>
<li><a href="#fs_fs_fchown_fd_uid_gid_callback">fs.fchown(fd, uid, gid, callback)</a></li>
<li><a href="#fs_fs_fchownsync_fd_uid_gid">fs.fchownSync(fd, uid, gid)</a></li>
<li><a href="#fs_fs_lchown_path_uid_gid_callback">fs.lchown(path, uid, gid, callback)</a></li>
<li><a href="#fs_fs_lchownsync_path_uid_gid">fs.lchownSync(path, uid, gid)</a></li>
<li><a href="#fs_fs_chmod_path_mode_callback">fs.chmod(path, mode, callback)</a></li>
<li><a href="#fs_fs_chmodsync_path_mode">fs.chmodSync(path, mode)</a></li>
<li><a href="#fs_fs_fchmod_fd_mode_callback">fs.fchmod(fd, mode, callback)</a></li>
<li><a href="#fs_fs_fchmodsync_fd_mode">fs.fchmodSync(fd, mode)</a></li>
<li><a href="#fs_fs_lchmod_path_mode_callback">fs.lchmod(path, mode, callback)</a></li>
<li><a href="#fs_fs_lchmodsync_path_mode">fs.lchmodSync(path, mode)</a></li>
<li><a href="#fs_fs_stat_path_callback">fs.stat(path, callback)</a></li>
<li><a href="#fs_fs_lstat_path_callback">fs.lstat(path, callback)</a></li>
<li><a href="#fs_fs_fstat_fd_callback">fs.fstat(fd, callback)</a></li>
<li><a href="#fs_fs_statsync_path">fs.statSync(path)</a></li>
<li><a href="#fs_fs_lstatsync_path">fs.lstatSync(path)</a></li>
<li><a href="#fs_fs_fstatsync_fd">fs.fstatSync(fd)</a></li>
<li><a href="#fs_fs_link_srcpath_dstpath_callback">fs.link(srcpath, dstpath, callback)</a></li>
<li><a href="#fs_fs_linksync_srcpath_dstpath">fs.linkSync(srcpath, dstpath)</a></li>
<li><a href="#fs_fs_symlink_srcpath_dstpath_type_callback">fs.symlink(srcpath, dstpath, [type], callback)</a></li>
<li><a href="#fs_fs_symlinksync_srcpath_dstpath_type">fs.symlinkSync(srcpath, dstpath, [type])</a></li>
<li><a href="#fs_fs_readlink_path_callback">fs.readlink(path, callback)</a></li>
<li><a href="#fs_fs_readlinksync_path">fs.readlinkSync(path)</a></li>
<li><a href="#fs_fs_realpath_path_cache_callback">fs.realpath(path, [cache], callback)</a></li>
<li><a href="#fs_fs_realpathsync_path_cache">fs.realpathSync(path, [cache])</a></li>
<li><a href="#fs_fs_unlink_path_callback">fs.unlink(path, callback)</a></li>
<li><a href="#fs_fs_unlinksync_path">fs.unlinkSync(path)</a></li>
<li><a href="#fs_fs_rmdir_path_callback">fs.rmdir(path, callback)</a></li>
<li><a href="#fs_fs_rmdirsync_path">fs.rmdirSync(path)</a></li>
<li><a href="#fs_fs_mkdir_path_mode_callback">fs.mkdir(path, [mode], callback)</a></li>
<li><a href="#fs_fs_mkdirsync_path_mode">fs.mkdirSync(path, [mode])</a></li>
<li><a href="#fs_fs_readdir_path_callback">fs.readdir(path, callback)</a></li>
<li><a href="#fs_fs_readdirsync_path">fs.readdirSync(path)</a></li>
<li><a href="#fs_fs_close_fd_callback">fs.close(fd, callback)</a></li>
<li><a href="#fs_fs_closesync_fd">fs.closeSync(fd)</a></li>
<li><a href="#fs_fs_open_path_flags_mode_callback">fs.open(path, flags, [mode], callback)</a></li>
<li><a href="#fs_fs_opensync_path_flags_mode">fs.openSync(path, flags, [mode])</a></li>
<li><a href="#fs_fs_utimes_path_atime_mtime_callback">fs.utimes(path, atime, mtime, callback)</a></li>
<li><a href="#fs_fs_utimessync_path_atime_mtime">fs.utimesSync(path, atime, mtime)</a></li>
<li><a href="#fs_fs_futimes_fd_atime_mtime_callback">fs.futimes(fd, atime, mtime, callback)</a></li>
<li><a href="#fs_fs_futimessync_fd_atime_mtime">fs.futimesSync(fd, atime, mtime)</a></li>
<li><a href="#fs_fs_fsync_fd_callback">fs.fsync(fd, callback)</a></li>
<li><a href="#fs_fs_fsyncsync_fd">fs.fsyncSync(fd)</a></li>
<li><a href="#fs_fs_write_fd_buffer_offset_length_position_callback">fs.write(fd, buffer, offset, length, position, callback)</a></li>
<li><a href="#fs_fs_writesync_fd_buffer_offset_length_position">fs.writeSync(fd, buffer, offset, length, position)</a></li>
<li><a href="#fs_fs_read_fd_buffer_offset_length_position_callback">fs.read(fd, buffer, offset, length, position, callback)</a></li>
<li><a href="#fs_fs_readsync_fd_buffer_offset_length_position">fs.readSync(fd, buffer, offset, length, position)</a></li>
<li><a href="#fs_fs_readfile_filename_options_callback">fs.readFile(filename, [options], callback)</a></li>
<li><a href="#fs_fs_readfilesync_filename_options">fs.readFileSync(filename, [options])</a></li>
<li><a href="#fs_fs_writefile_filename_data_options_callback">fs.writeFile(filename, data, [options], callback)</a></li>
<li><a href="#fs_fs_writefilesync_filename_data_options">fs.writeFileSync(filename, data, [options])</a></li>
<li><a href="#fs_fs_appendfile_filename_data_options_callback">fs.appendFile(filename, data, [options], callback)</a></li>
<li><a href="#fs_fs_appendfilesync_filename_data_options">fs.appendFileSync(filename, data, [options])</a></li>
<li><a href="#fs_fs_watchfile_filename_options_listener">fs.watchFile(filename, [options], listener)</a></li>
<li><a href="#fs_fs_unwatchfile_filename_listener">fs.unwatchFile(filename, [listener])</a></li>
<li><a href="#fs_fs_watch_filename_options_listener">fs.watch(filename, [options], [listener])</a><ul>
<li><a href="#fs_caveats">Caveats</a><ul>
<li><a href="#fs_availability">Availability</a></li>
<li><a href="#fs_filename_argument">Filename Argument</a></li>
</ul>
</li>
</ul>
</li>
<li><a href="#fs_fs_exists_path_callback">fs.exists(path, callback)</a></li>
<li><a href="#fs_fs_existssync_path">fs.existsSync(path)</a></li>
<li><a href="#fs_class_fs_stats">Class: fs.Stats</a></li>
<li><a href="#fs_fs_createreadstream_path_options">fs.createReadStream(path, [options])</a></li>
<li><a href="#fs_class_fs_readstream">Class: fs.ReadStream</a><ul>
<li><a href="#fs_event_open">Event: 'open'</a></li>
</ul>
</li>
<li><a href="#fs_fs_createwritestream_path_options">fs.createWriteStream(path, [options])</a></li>
<li><a href="#fs_class_fs_writestream">Class: fs.WriteStream</a><ul>
<li><a href="#fs_event_open_1">Event: 'open'</a></li>
<li><a href="#fs_file_byteswritten">file.bytesWritten</a></li>
</ul>
</li>
<li><a href="#fs_class_fs_fswatcher">Class: fs.FSWatcher</a><ul>
<li><a href="#fs_watcher_close">watcher.close()</a></li>
<li><a href="#fs_event_change">Event: 'change'</a></li>
<li><a href="#fs_event_error">Event: 'error'</a></li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
<div id="apicontent">
<h1>File System<span><a class="mark" href="#fs_file_system" id="fs_file_system">#</a></span></h1>
<pre class="api_stability_3">Stability: 3 - Stable</pre><!--name=fs-->
<p>File I/O is provided by simple wrappers around standard POSIX functions. To
use this module do <code>require('fs')</code>. All the methods have asynchronous and
synchronous forms.
</p>
<p>The asynchronous form always take a completion callback as its last argument.
The arguments passed to the completion callback depend on the method, but the
first argument is always reserved for an exception. If the operation was
completed successfully, then the first argument will be <code>null</code> or <code>undefined</code>.
</p>
<p>When using the synchronous form any exceptions are immediately thrown.
You can use try/catch to handle exceptions or allow them to bubble up.
</p>
<p>Here is an example of the asynchronous version:
</p>
<pre><code>var fs = require('fs');
fs.unlink('/tmp/hello', function (err) {
if (err) throw err;
console.log('successfully deleted /tmp/hello');
});</code></pre>
<p>Here is the synchronous version:
</p>
<pre><code>var fs = require('fs');
fs.unlinkSync('/tmp/hello')
console.log('successfully deleted /tmp/hello');</code></pre>
<p>With the asynchronous methods there is no guaranteed ordering. So the
following is prone to error:
</p>
<pre><code>fs.rename('/tmp/hello', '/tmp/world', function (err) {
if (err) throw err;
console.log('renamed complete');
});
fs.stat('/tmp/world', function (err, stats) {
if (err) throw err;
console.log('stats: ' + JSON.stringify(stats));
});</code></pre>
<p>It could be that <code>fs.stat</code> is executed before <code>fs.rename</code>.
The correct way to do this is to chain the callbacks.
</p>
<pre><code>fs.rename('/tmp/hello', '/tmp/world', function (err) {
if (err) throw err;
fs.stat('/tmp/world', function (err, stats) {
if (err) throw err;
console.log('stats: ' + JSON.stringify(stats));
});
});</code></pre>
<p>In busy processes, the programmer is <em>strongly encouraged</em> to use the
asynchronous versions of these calls. The synchronous versions will block
the entire process until they complete--halting all connections.
</p>
<p>Relative path to filename can be used, remember however that this path will be
relative to <code>process.cwd()</code>.
</p>
<p>Most fs functions let you omit the callback argument. If you do, a default
callback is used that ignores errors, but prints a deprecation
warning.
</p>
<p><strong>IMPORTANT</strong>: Omitting the callback is deprecated. v0.12 will throw the
errors as exceptions.
</p>
<h2>fs.rename(oldPath, newPath, callback)<span><a class="mark" href="#fs_fs_rename_oldpath_newpath_callback" id="fs_fs_rename_oldpath_newpath_callback">#</a></span></h2>
<p>Asynchronous rename(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.renameSync(oldPath, newPath)<span><a class="mark" href="#fs_fs_renamesync_oldpath_newpath" id="fs_fs_renamesync_oldpath_newpath">#</a></span></h2>
<p>Synchronous rename(2).
</p>
<h2>fs.ftruncate(fd, len, callback)<span><a class="mark" href="#fs_fs_ftruncate_fd_len_callback" id="fs_fs_ftruncate_fd_len_callback">#</a></span></h2>
<p>Asynchronous ftruncate(2). No arguments other than a possible exception are
given to the completion callback.
</p>
<h2>fs.ftruncateSync(fd, len)<span><a class="mark" href="#fs_fs_ftruncatesync_fd_len" id="fs_fs_ftruncatesync_fd_len">#</a></span></h2>
<p>Synchronous ftruncate(2).
</p>
<h2>fs.truncate(path, len, callback)<span><a class="mark" href="#fs_fs_truncate_path_len_callback" id="fs_fs_truncate_path_len_callback">#</a></span></h2>
<p>Asynchronous truncate(2). No arguments other than a possible exception are
given to the completion callback.
</p>
<h2>fs.truncateSync(path, len)<span><a class="mark" href="#fs_fs_truncatesync_path_len" id="fs_fs_truncatesync_path_len">#</a></span></h2>
<p>Synchronous truncate(2).
</p>
<h2>fs.chown(path, uid, gid, callback)<span><a class="mark" href="#fs_fs_chown_path_uid_gid_callback" id="fs_fs_chown_path_uid_gid_callback">#</a></span></h2>
<p>Asynchronous chown(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.chownSync(path, uid, gid)<span><a class="mark" href="#fs_fs_chownsync_path_uid_gid" id="fs_fs_chownsync_path_uid_gid">#</a></span></h2>
<p>Synchronous chown(2).
</p>
<h2>fs.fchown(fd, uid, gid, callback)<span><a class="mark" href="#fs_fs_fchown_fd_uid_gid_callback" id="fs_fs_fchown_fd_uid_gid_callback">#</a></span></h2>
<p>Asynchronous fchown(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.fchownSync(fd, uid, gid)<span><a class="mark" href="#fs_fs_fchownsync_fd_uid_gid" id="fs_fs_fchownsync_fd_uid_gid">#</a></span></h2>
<p>Synchronous fchown(2).
</p>
<h2>fs.lchown(path, uid, gid, callback)<span><a class="mark" href="#fs_fs_lchown_path_uid_gid_callback" id="fs_fs_lchown_path_uid_gid_callback">#</a></span></h2>
<p>Asynchronous lchown(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.lchownSync(path, uid, gid)<span><a class="mark" href="#fs_fs_lchownsync_path_uid_gid" id="fs_fs_lchownsync_path_uid_gid">#</a></span></h2>
<p>Synchronous lchown(2).
</p>
<h2>fs.chmod(path, mode, callback)<span><a class="mark" href="#fs_fs_chmod_path_mode_callback" id="fs_fs_chmod_path_mode_callback">#</a></span></h2>
<p>Asynchronous chmod(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.chmodSync(path, mode)<span><a class="mark" href="#fs_fs_chmodsync_path_mode" id="fs_fs_chmodsync_path_mode">#</a></span></h2>
<p>Synchronous chmod(2).
</p>
<h2>fs.fchmod(fd, mode, callback)<span><a class="mark" href="#fs_fs_fchmod_fd_mode_callback" id="fs_fs_fchmod_fd_mode_callback">#</a></span></h2>
<p>Asynchronous fchmod(2). No arguments other than a possible exception
are given to the completion callback.
</p>
<h2>fs.fchmodSync(fd, mode)<span><a class="mark" href="#fs_fs_fchmodsync_fd_mode" id="fs_fs_fchmodsync_fd_mode">#</a></span></h2>
<p>Synchronous fchmod(2).
</p>
<h2>fs.lchmod(path, mode, callback)<span><a class="mark" href="#fs_fs_lchmod_path_mode_callback" id="fs_fs_lchmod_path_mode_callback">#</a></span></h2>
<p>Asynchronous lchmod(2). No arguments other than a possible exception
are given to the completion callback.
</p>
<p>Only available on Mac OS X.
</p>
<h2>fs.lchmodSync(path, mode)<span><a class="mark" href="#fs_fs_lchmodsync_path_mode" id="fs_fs_lchmodsync_path_mode">#</a></span></h2>
<p>Synchronous lchmod(2).
</p>
<h2>fs.stat(path, callback)<span><a class="mark" href="#fs_fs_stat_path_callback" id="fs_fs_stat_path_callback">#</a></span></h2>
<p>Asynchronous stat(2). The callback gets two arguments <code>(err, stats)</code> where
<code>stats</code> is a <a href="#fs_class_fs_stats">fs.Stats</a> object. See the <a href="#fs_class_fs_stats">fs.Stats</a>
section below for more information.
</p>
<h2>fs.lstat(path, callback)<span><a class="mark" href="#fs_fs_lstat_path_callback" id="fs_fs_lstat_path_callback">#</a></span></h2>
<p>Asynchronous lstat(2). The callback gets two arguments <code>(err, stats)</code> where
<code>stats</code> is a <code>fs.Stats</code> object. <code>lstat()</code> is identical to <code>stat()</code>, except that if
<code>path</code> is a symbolic link, then the link itself is stat-ed, not the file that it
refers to.
</p>
<h2>fs.fstat(fd, callback)<span><a class="mark" href="#fs_fs_fstat_fd_callback" id="fs_fs_fstat_fd_callback">#</a></span></h2>
<p>Asynchronous fstat(2). The callback gets two arguments <code>(err, stats)</code> where
<code>stats</code> is a <code>fs.Stats</code> object. <code>fstat()</code> is identical to <code>stat()</code>, except that
the file to be stat-ed is specified by the file descriptor <code>fd</code>.
</p>
<h2>fs.statSync(path)<span><a class="mark" href="#fs_fs_statsync_path" id="fs_fs_statsync_path">#</a></span></h2>
<p>Synchronous stat(2). Returns an instance of <code>fs.Stats</code>.
</p>
<h2>fs.lstatSync(path)<span><a class="mark" href="#fs_fs_lstatsync_path" id="fs_fs_lstatsync_path">#</a></span></h2>
<p>Synchronous lstat(2). Returns an instance of <code>fs.Stats</code>.
</p>
<h2>fs.fstatSync(fd)<span><a class="mark" href="#fs_fs_fstatsync_fd" id="fs_fs_fstatsync_fd">#</a></span></h2>
<p>Synchronous fstat(2). Returns an instance of <code>fs.Stats</code>.
</p>
<h2>fs.link(srcpath, dstpath, callback)<span><a class="mark" href="#fs_fs_link_srcpath_dstpath_callback" id="fs_fs_link_srcpath_dstpath_callback">#</a></span></h2>
<p>Asynchronous link(2). No arguments other than a possible exception are given to
the completion callback.
</p>
<h2>fs.linkSync(srcpath, dstpath)<span><a class="mark" href="#fs_fs_linksync_srcpath_dstpath" id="fs_fs_linksync_srcpath_dstpath">#</a></span></h2>
<p>Synchronous link(2).
</p>
<h2>fs.symlink(srcpath, dstpath, [type], callback)<span><a class="mark" href="#fs_fs_symlink_srcpath_dstpath_type_callback" id="fs_fs_symlink_srcpath_dstpath_type_callback">#</a></span></h2>
<p>Asynchronous symlink(2). No arguments other than a possible exception are given
to the completion callback.
The <code>type</code> argument can be set to <code>'dir'</code>, <code>'file'</code>, or <code>'junction'</code> (default
is <code>'file'</code>) and is only available on Windows (ignored on other platforms).
Note that Windows junction points require the destination path to be absolute. When using
<code>'junction'</code>, the <code>destination</code> argument will automatically be normalized to absolute path.
</p>
<h2>fs.symlinkSync(srcpath, dstpath, [type])<span><a class="mark" href="#fs_fs_symlinksync_srcpath_dstpath_type" id="fs_fs_symlinksync_srcpath_dstpath_type">#</a></span></h2>
<p>Synchronous symlink(2).
</p>
<h2>fs.readlink(path, callback)<span><a class="mark" href="#fs_fs_readlink_path_callback" id="fs_fs_readlink_path_callback">#</a></span></h2>
<p>Asynchronous readlink(2). The callback gets two arguments <code>(err,
linkString)</code>.
</p>
<h2>fs.readlinkSync(path)<span><a class="mark" href="#fs_fs_readlinksync_path" id="fs_fs_readlinksync_path">#</a></span></h2>
<p>Synchronous readlink(2). Returns the symbolic link's string value.
</p>
<h2>fs.realpath(path, [cache], callback)<span><a class="mark" href="#fs_fs_realpath_path_cache_callback" id="fs_fs_realpath_path_cache_callback">#</a></span></h2>
<p>Asynchronous realpath(2). The <code>callback</code> gets two arguments <code>(err,
resolvedPath)</code>. May use <code>process.cwd</code> to resolve relative paths. <code>cache</code> is an
object literal of mapped paths that can be used to force a specific path
resolution or avoid additional <code>fs.stat</code> calls for known real paths.
</p>
<p>Example:
</p>
<pre><code>var cache = {'/etc':'/private/etc'};
fs.realpath('/etc/passwd', cache, function (err, resolvedPath) {
if (err) throw err;
console.log(resolvedPath);
});</code></pre>
<h2>fs.realpathSync(path, [cache])<span><a class="mark" href="#fs_fs_realpathsync_path_cache" id="fs_fs_realpathsync_path_cache">#</a></span></h2>
<p>Synchronous realpath(2). Returns the resolved path.
</p>
<h2>fs.unlink(path, callback)<span><a class="mark" href="#fs_fs_unlink_path_callback" id="fs_fs_unlink_path_callback">#</a></span></h2>
<p>Asynchronous unlink(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.unlinkSync(path)<span><a class="mark" href="#fs_fs_unlinksync_path" id="fs_fs_unlinksync_path">#</a></span></h2>
<p>Synchronous unlink(2).
</p>
<h2>fs.rmdir(path, callback)<span><a class="mark" href="#fs_fs_rmdir_path_callback" id="fs_fs_rmdir_path_callback">#</a></span></h2>
<p>Asynchronous rmdir(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.rmdirSync(path)<span><a class="mark" href="#fs_fs_rmdirsync_path" id="fs_fs_rmdirsync_path">#</a></span></h2>
<p>Synchronous rmdir(2).
</p>
<h2>fs.mkdir(path, [mode], callback)<span><a class="mark" href="#fs_fs_mkdir_path_mode_callback" id="fs_fs_mkdir_path_mode_callback">#</a></span></h2>
<p>Asynchronous mkdir(2). No arguments other than a possible exception are given
to the completion callback. <code>mode</code> defaults to <code>0777</code>.
</p>
<h2>fs.mkdirSync(path, [mode])<span><a class="mark" href="#fs_fs_mkdirsync_path_mode" id="fs_fs_mkdirsync_path_mode">#</a></span></h2>
<p>Synchronous mkdir(2).
</p>
<h2>fs.readdir(path, callback)<span><a class="mark" href="#fs_fs_readdir_path_callback" id="fs_fs_readdir_path_callback">#</a></span></h2>
<p>Asynchronous readdir(3). Reads the contents of a directory.
The callback gets two arguments <code>(err, files)</code> where <code>files</code> is an array of
the names of the files in the directory excluding <code>'.'</code> and <code>'..'</code>.
</p>
<h2>fs.readdirSync(path)<span><a class="mark" href="#fs_fs_readdirsync_path" id="fs_fs_readdirsync_path">#</a></span></h2>
<p>Synchronous readdir(3). Returns an array of filenames excluding <code>'.'</code> and
<code>'..'</code>.
</p>
<h2>fs.close(fd, callback)<span><a class="mark" href="#fs_fs_close_fd_callback" id="fs_fs_close_fd_callback">#</a></span></h2>
<p>Asynchronous close(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.closeSync(fd)<span><a class="mark" href="#fs_fs_closesync_fd" id="fs_fs_closesync_fd">#</a></span></h2>
<p>Synchronous close(2).
</p>
<h2>fs.open(path, flags, [mode], callback)<span><a class="mark" href="#fs_fs_open_path_flags_mode_callback" id="fs_fs_open_path_flags_mode_callback">#</a></span></h2>
<p>Asynchronous file open. See open(2). <code>flags</code> can be:
</p>
<ul>
<li><p><code>'r'</code> - Open file for reading.
An exception occurs if the file does not exist.</p>
</li>
<li><p><code>'r+'</code> - Open file for reading and writing.
An exception occurs if the file does not exist.</p>
</li>
<li><p><code>'rs'</code> - Open file for reading in synchronous mode. Instructs the operating
system to bypass the local file system cache.</p>
<p>This is primarily useful for opening files on NFS mounts as it allows you to
skip the potentially stale local cache. It has a very real impact on I/O
performance so don't use this flag unless you need it.</p>
<p>Note that this doesn't turn <code>fs.open()</code> into a synchronous blocking call.
If that's what you want then you should be using <code>fs.openSync()</code></p>
</li>
<li><p><code>'rs+'</code> - Open file for reading and writing, telling the OS to open it
synchronously. See notes for <code>'rs'</code> about using this with caution.</p>
</li>
<li><p><code>'w'</code> - Open file for writing.
The file is created (if it does not exist) or truncated (if it exists).</p>
</li>
<li><p><code>'wx'</code> - Like <code>'w'</code> but fails if <code>path</code> exists.</p>
</li>
<li><p><code>'w+'</code> - Open file for reading and writing.
The file is created (if it does not exist) or truncated (if it exists).</p>
</li>
<li><p><code>'wx+'</code> - Like <code>'w+'</code> but fails if <code>path</code> exists.</p>
</li>
<li><p><code>'a'</code> - Open file for appending.
The file is created if it does not exist.</p>
</li>
<li><p><code>'ax'</code> - Like <code>'a'</code> but fails if <code>path</code> exists.</p>
</li>
<li><p><code>'a+'</code> - Open file for reading and appending.
The file is created if it does not exist.</p>
</li>
<li><p><code>'ax+'</code> - Like <code>'a+'</code> but fails if <code>path</code> exists.</p>
</li>
</ul>
<p><code>mode</code> sets the file mode (permission and sticky bits), but only if the file was
created. It defaults to <code>0666</code>, readable and writeable.
</p>
<p>The callback gets two arguments <code>(err, fd)</code>.
</p>
<p>The exclusive flag <code>'x'</code> (<code>O_EXCL</code> flag in open(2)) ensures that <code>path</code> is newly
created. On POSIX systems, <code>path</code> is considered to exist even if it is a symlink
to a non-existent file. The exclusive flag may or may not work with network file
systems.
</p>
<p>On Linux, positional writes don't work when the file is opened in append mode.
The kernel ignores the position argument and always appends the data to
the end of the file.
</p>
<h2>fs.openSync(path, flags, [mode])<span><a class="mark" href="#fs_fs_opensync_path_flags_mode" id="fs_fs_opensync_path_flags_mode">#</a></span></h2>
<p>Synchronous version of <code>fs.open()</code>.
</p>
<h2>fs.utimes(path, atime, mtime, callback)<span><a class="mark" href="#fs_fs_utimes_path_atime_mtime_callback" id="fs_fs_utimes_path_atime_mtime_callback">#</a></span></h2>
<h2>fs.utimesSync(path, atime, mtime)<span><a class="mark" href="#fs_fs_utimessync_path_atime_mtime" id="fs_fs_utimessync_path_atime_mtime">#</a></span></h2>
<p>Change file timestamps of the file referenced by the supplied path.
</p>
<h2>fs.futimes(fd, atime, mtime, callback)<span><a class="mark" href="#fs_fs_futimes_fd_atime_mtime_callback" id="fs_fs_futimes_fd_atime_mtime_callback">#</a></span></h2>
<h2>fs.futimesSync(fd, atime, mtime)<span><a class="mark" href="#fs_fs_futimessync_fd_atime_mtime" id="fs_fs_futimessync_fd_atime_mtime">#</a></span></h2>
<p>Change the file timestamps of a file referenced by the supplied file
descriptor.
</p>
<h2>fs.fsync(fd, callback)<span><a class="mark" href="#fs_fs_fsync_fd_callback" id="fs_fs_fsync_fd_callback">#</a></span></h2>
<p>Asynchronous fsync(2). No arguments other than a possible exception are given
to the completion callback.
</p>
<h2>fs.fsyncSync(fd)<span><a class="mark" href="#fs_fs_fsyncsync_fd" id="fs_fs_fsyncsync_fd">#</a></span></h2>
<p>Synchronous fsync(2).
</p>
<h2>fs.write(fd, buffer, offset, length, position, callback)<span><a class="mark" href="#fs_fs_write_fd_buffer_offset_length_position_callback" id="fs_fs_write_fd_buffer_offset_length_position_callback">#</a></span></h2>
<p>Write <code>buffer</code> to the file specified by <code>fd</code>.
</p>
<p><code>offset</code> and <code>length</code> determine the part of the buffer to be written.
</p>
<p><code>position</code> refers to the offset from the beginning of the file where this data
should be written. If <code>position</code> is <code>null</code>, the data will be written at the
current position.
See pwrite(2).
</p>
<p>The callback will be given three arguments <code>(err, written, buffer)</code> where <code>written</code>
specifies how many <em>bytes</em> were written from <code>buffer</code>.
</p>
<p>Note that it is unsafe to use <code>fs.write</code> multiple times on the same file
without waiting for the callback. For this scenario,
<code>fs.createWriteStream</code> is strongly recommended.
</p>
<p>On Linux, positional writes don't work when the file is opened in append mode.
The kernel ignores the position argument and always appends the data to
the end of the file.
</p>
<h2>fs.writeSync(fd, buffer, offset, length, position)<span><a class="mark" href="#fs_fs_writesync_fd_buffer_offset_length_position" id="fs_fs_writesync_fd_buffer_offset_length_position">#</a></span></h2>
<p>Synchronous version of <code>fs.write()</code>. Returns the number of bytes written.
</p>
<h2>fs.read(fd, buffer, offset, length, position, callback)<span><a class="mark" href="#fs_fs_read_fd_buffer_offset_length_position_callback" id="fs_fs_read_fd_buffer_offset_length_position_callback">#</a></span></h2>
<p>Read data from the file specified by <code>fd</code>.
</p>
<p><code>buffer</code> is the buffer that the data will be written to.
</p>
<p><code>offset</code> is the offset in the buffer to start writing at.
</p>
<p><code>length</code> is an integer specifying the number of bytes to read.
</p>
<p><code>position</code> is an integer specifying where to begin reading from in the file.
If <code>position</code> is <code>null</code>, data will be read from the current file position.
</p>
<p>The callback is given the three arguments, <code>(err, bytesRead, buffer)</code>.
</p>
<h2>fs.readSync(fd, buffer, offset, length, position)<span><a class="mark" href="#fs_fs_readsync_fd_buffer_offset_length_position" id="fs_fs_readsync_fd_buffer_offset_length_position">#</a></span></h2>
<p>Synchronous version of <code>fs.read</code>. Returns the number of <code>bytesRead</code>.
</p>
<h2>fs.readFile(filename, [options], callback)<span><a class="mark" href="#fs_fs_readfile_filename_options_callback" id="fs_fs_readfile_filename_options_callback">#</a></span></h2>
<div class="signature"><ul>
<li><code>filename</code> <span class="type">String</span></li>
<li><code>options</code> <span class="type">Object</span><ul>
<li><code>encoding</code> <span class="type">String | Null</span> default = <code>null</code></li>
<li><code>flag</code> <span class="type">String</span> default = <code>'r'</code></li>
</ul>
</li>
<li><code>callback</code> <span class="type">Function</span></li>
</div></ul>
<p>Asynchronously reads the entire contents of a file. Example:
</p>
<pre><code>fs.readFile('/etc/passwd', function (err, data) {
if (err) throw err;
console.log(data);
});</code></pre>
<p>The callback is passed two arguments <code>(err, data)</code>, where <code>data</code> is the
contents of the file.
</p>
<p>If no encoding is specified, then the raw buffer is returned.
</p>
<h2>fs.readFileSync(filename, [options])<span><a class="mark" href="#fs_fs_readfilesync_filename_options" id="fs_fs_readfilesync_filename_options">#</a></span></h2>
<p>Synchronous version of <code>fs.readFile</code>. Returns the contents of the <code>filename</code>.
</p>
<p>If the <code>encoding</code> option is specified then this function returns a
string. Otherwise it returns a buffer.
</p>
<h2>fs.writeFile(filename, data, [options], callback)<span><a class="mark" href="#fs_fs_writefile_filename_data_options_callback" id="fs_fs_writefile_filename_data_options_callback">#</a></span></h2>
<div class="signature"><ul>
<li><code>filename</code> <span class="type">String</span></li>
<li><code>data</code> <span class="type">String | Buffer</span></li>
<li><code>options</code> <span class="type">Object</span><ul>
<li><code>encoding</code> <span class="type">String | Null</span> default = <code>'utf8'</code></li>
<li><code>mode</code> <span class="type">Number</span> default = <code>438</code> (aka <code>0666</code> in Octal)</li>
<li><code>flag</code> <span class="type">String</span> default = <code>'w'</code></li>
</ul>
</li>
<li><code>callback</code> <span class="type">Function</span></li>
</div></ul>
<p>Asynchronously writes data to a file, replacing the file if it already exists.
<code>data</code> can be a string or a buffer.
</p>
<p>The <code>encoding</code> option is ignored if <code>data</code> is a buffer. It defaults
to <code>'utf8'</code>.
</p>
<p>Example:
</p>
<pre><code>fs.writeFile('message.txt', 'Hello Node', function (err) {
if (err) throw err;
console.log('It\'s saved!');
});</code></pre>
<h2>fs.writeFileSync(filename, data, [options])<span><a class="mark" href="#fs_fs_writefilesync_filename_data_options" id="fs_fs_writefilesync_filename_data_options">#</a></span></h2>
<p>The synchronous version of <code>fs.writeFile</code>.
</p>
<h2>fs.appendFile(filename, data, [options], callback)<span><a class="mark" href="#fs_fs_appendfile_filename_data_options_callback" id="fs_fs_appendfile_filename_data_options_callback">#</a></span></h2>
<div class="signature"><ul>
<li><code>filename</code> <span class="type">String</span></li>
<li><code>data</code> <span class="type">String | Buffer</span></li>
<li><code>options</code> <span class="type">Object</span><ul>
<li><code>encoding</code> <span class="type">String | Null</span> default = <code>'utf8'</code></li>
<li><code>mode</code> <span class="type">Number</span> default = <code>438</code> (aka <code>0666</code> in Octal)</li>
<li><code>flag</code> <span class="type">String</span> default = <code>'a'</code></li>
</ul>
</li>
<li><code>callback</code> <span class="type">Function</span></li>
</div></ul>
<p>Asynchronously append data to a file, creating the file if it not yet exists.
<code>data</code> can be a string or a buffer.
</p>
<p>Example:
</p>
<pre><code>fs.appendFile('message.txt', 'data to append', function (err) {
if (err) throw err;
console.log('The "data to append" was appended to file!');
});</code></pre>
<h2>fs.appendFileSync(filename, data, [options])<span><a class="mark" href="#fs_fs_appendfilesync_filename_data_options" id="fs_fs_appendfilesync_filename_data_options">#</a></span></h2>
<p>The synchronous version of <code>fs.appendFile</code>.
</p>
<h2>fs.watchFile(filename, [options], listener)<span><a class="mark" href="#fs_fs_watchfile_filename_options_listener" id="fs_fs_watchfile_filename_options_listener">#</a></span></h2>
<pre class="api_stability_2">Stability: 2 - Unstable. Use fs.watch instead, if possible.</pre><p>Watch for changes on <code>filename</code>. The callback <code>listener</code> will be called each
time the file is accessed.
</p>
<p>The second argument is optional. The <code>options</code> if provided should be an object
containing two members a boolean, <code>persistent</code>, and <code>interval</code>. <code>persistent</code>
indicates whether the process should continue to run as long as files are
being watched. <code>interval</code> indicates how often the target should be polled,
in milliseconds. The default is <code>{ persistent: true, interval: 5007 }</code>.
</p>
<p>The <code>listener</code> gets two arguments the current stat object and the previous
stat object:
</p>
<pre><code>fs.watchFile('message.text', function (curr, prev) {
console.log('the current mtime is: ' + curr.mtime);
console.log('the previous mtime was: ' + prev.mtime);
});</code></pre>
<p>These stat objects are instances of <code>fs.Stat</code>.
</p>
<p>If you want to be notified when the file was modified, not just accessed
you need to compare <code>curr.mtime</code> and <code>prev.mtime</code>.
</p>
<h2>fs.unwatchFile(filename, [listener])<span><a class="mark" href="#fs_fs_unwatchfile_filename_listener" id="fs_fs_unwatchfile_filename_listener">#</a></span></h2>
<pre class="api_stability_2">Stability: 2 - Unstable. Use fs.watch instead, if possible.</pre><p>Stop watching for changes on <code>filename</code>. If <code>listener</code> is specified, only that
particular listener is removed. Otherwise, <em>all</em> listeners are removed and you
have effectively stopped watching <code>filename</code>.
</p>
<p>Calling <code>fs.unwatchFile()</code> with a filename that is not being watched is a
no-op, not an error.
</p>
<h2>fs.watch(filename, [options], [listener])<span><a class="mark" href="#fs_fs_watch_filename_options_listener" id="fs_fs_watch_filename_options_listener">#</a></span></h2>
<pre class="api_stability_2">Stability: 2 - Unstable.</pre><p>Watch for changes on <code>filename</code>, where <code>filename</code> is either a file or a
directory. The returned object is a <a href="#fs_class_fs_fswatcher">fs.FSWatcher</a>.
</p>
<p>The second argument is optional. The <code>options</code> if provided should be an object
containing a boolean member <code>persistent</code>, which indicates whether the process
should continue to run as long as files are being watched. The default is
<code>{ persistent: true }</code>.
</p>
<p>The listener callback gets two arguments <code>(event, filename)</code>. <code>event</code> is either
'rename' or 'change', and <code>filename</code> is the name of the file which triggered
the event.
</p>
<h3>Caveats<span><a class="mark" href="#fs_caveats" id="fs_caveats">#</a></span></h3>
<!--type=misc-->
<p>The <code>fs.watch</code> API is not 100% consistent across platforms, and is
unavailable in some situations.
</p>
<h4>Availability<span><a class="mark" href="#fs_availability" id="fs_availability">#</a></span></h4>
<!--type=misc-->
<p>This feature depends on the underlying operating system providing a way
to be notified of filesystem changes.
</p>
<ul>
<li>On Linux systems, this uses <code>inotify</code>.</li>
<li>On BSD systems (including OS X), this uses <code>kqueue</code>.</li>
<li>On SunOS systems (including Solaris and SmartOS), this uses <code>event ports</code>.</li>
<li>On Windows systems, this feature depends on <code>ReadDirectoryChangesW</code>.</li>
</ul>
<p>If the underlying functionality is not available for some reason, then
<code>fs.watch</code> will not be able to function. For example, watching files or
directories on network file systems (NFS, SMB, etc.) often doesn't work
reliably or at all.
</p>
<p>You can still use <code>fs.watchFile</code>, which uses stat polling, but it is slower and
less reliable.
</p>
<h4>Filename Argument<span><a class="mark" href="#fs_filename_argument" id="fs_filename_argument">#</a></span></h4>
<!--type=misc-->
<p>Providing <code>filename</code> argument in the callback is not supported
on every platform (currently it's only supported on Linux and Windows). Even
on supported platforms <code>filename</code> is not always guaranteed to be provided.
Therefore, don't assume that <code>filename</code> argument is always provided in the
callback, and have some fallback logic if it is null.
</p>
<pre><code>fs.watch('somedir', function (event, filename) {
console.log('event is: ' + event);
if (filename) {
console.log('filename provided: ' + filename);
} else {
console.log('filename not provided');
}
});</code></pre>
<h2>fs.exists(path, callback)<span><a class="mark" href="#fs_fs_exists_path_callback" id="fs_fs_exists_path_callback">#</a></span></h2>
<p>Test whether or not the given path exists by checking with the file system.
Then call the <code>callback</code> argument with either true or false. Example:
</p>
<pre><code>fs.exists('/etc/passwd', function (exists) {
util.debug(exists ? "it's there" : "no passwd!");
});</code></pre>
<p><code>fs.exists()</code> is an anachronism and exists only for historical reasons.
There should almost never be a reason to use it in your own code.
</p>
<p>In particular, checking if a file exists before opening it is an anti-pattern
that leaves you vulnerable to race conditions: another process may remove the
file between the calls to <code>fs.exists()</code> and <code>fs.open()</code>. Just open the file
and handle the error when it's not there.
</p>
<h2>fs.existsSync(path)<span><a class="mark" href="#fs_fs_existssync_path" id="fs_fs_existssync_path">#</a></span></h2>
<p>Synchronous version of <code>fs.exists</code>.
</p>
<h2>Class: fs.Stats<span><a class="mark" href="#fs_class_fs_stats" id="fs_class_fs_stats">#</a></span></h2>
<p>Objects returned from <code>fs.stat()</code>, <code>fs.lstat()</code> and <code>fs.fstat()</code> and their
synchronous counterparts are of this type.
</p>
<ul>
<li><code>stats.isFile()</code></li>
<li><code>stats.isDirectory()</code></li>
<li><code>stats.isBlockDevice()</code></li>
<li><code>stats.isCharacterDevice()</code></li>
<li><code>stats.isSymbolicLink()</code> (only valid with <code>fs.lstat()</code>)</li>
<li><code>stats.isFIFO()</code></li>
<li><code>stats.isSocket()</code></li>
</ul>
<p>For a regular file <code>util.inspect(stats)</code> would return a string very
similar to this:
</p>
<pre><code>{ dev: 2114,
ino: 48064969,
mode: 33188,
nlink: 1,
uid: 85,
gid: 100,
rdev: 0,
size: 527,
blksize: 4096,
blocks: 8,
atime: Mon, 10 Oct 2011 23:24:11 GMT,
mtime: Mon, 10 Oct 2011 23:24:11 GMT,
ctime: Mon, 10 Oct 2011 23:24:11 GMT }</code></pre>
<p>Please note that <code>atime</code>, <code>mtime</code> and <code>ctime</code> are instances
of <a href="https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date">Date</a> object and to compare the values of
these objects you should use appropriate methods. For most
general uses <a href="https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date/getTime">getTime()</a> will return
the number of milliseconds elapsed since <em>1 January 1970
00:00:00 UTC</em> and this integer should be sufficient for
any comparison, however there additional methods which can
be used for displaying fuzzy information. More details can
be found in the <a href="https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date">MDN JavaScript Reference</a> page.
</p>
<h2>fs.createReadStream(path, [options])<span><a class="mark" href="#fs_fs_createreadstream_path_options" id="fs_fs_createreadstream_path_options">#</a></span></h2>
<p>Returns a new ReadStream object (See <code>Readable Stream</code>).
</p>
<p><code>options</code> is an object with the following defaults:
</p>
<pre><code>{ flags: 'r',
encoding: null,
fd: null,
mode: 0666,
autoClose: true
}</code></pre>
<p><code>options</code> can include <code>start</code> and <code>end</code> values to read a range of bytes from
the file instead of the entire file. Both <code>start</code> and <code>end</code> are inclusive and
start at 0. The <code>encoding</code> can be <code>'utf8'</code>, <code>'ascii'</code>, or <code>'base64'</code>.
</p>
<p>If <code>autoClose</code> is false, then the file descriptor won't be closed, even if
there's an error. It is your responsiblity to close it and make sure
there's no file descriptor leak. If <code>autoClose</code> is set to true (default
behavior), on <code>error</code> or <code>end</code> the file descriptor will be closed
automatically.
</p>
<p>An example to read the last 10 bytes of a file which is 100 bytes long:
</p>
<pre><code>fs.createReadStream('sample.txt', {start: 90, end: 99});</code></pre>
<h2>Class: fs.ReadStream<span><a class="mark" href="#fs_class_fs_readstream" id="fs_class_fs_readstream">#</a></span></h2>
<p><code>ReadStream</code> is a <a href="stream.html#stream_class_stream_readable">Readable Stream</a>.
</p>
<h3>Event: 'open'<span><a class="mark" href="#fs_event_open" id="fs_event_open">#</a></span></h3>
<div class="signature"><ul>
<li><code>fd</code> <span class="type">Integer</span> file descriptor used by the ReadStream.</li>
</div></ul>
<p>Emitted when the ReadStream's file is opened.
</p>
<h2>fs.createWriteStream(path, [options])<span><a class="mark" href="#fs_fs_createwritestream_path_options" id="fs_fs_createwritestream_path_options">#</a></span></h2>
<p>Returns a new WriteStream object (See <code>Writable Stream</code>).
</p>
<p><code>options</code> is an object with the following defaults:
</p>
<pre><code>{ flags: 'w',
encoding: null,
mode: 0666 }</code></pre>
<p><code>options</code> may also include a <code>start</code> option to allow writing data at
some position past the beginning of the file. Modifying a file rather
than replacing it may require a <code>flags</code> mode of <code>r+</code> rather than the
default mode <code>w</code>.
</p>
<h2>Class: fs.WriteStream<span><a class="mark" href="#fs_class_fs_writestream" id="fs_class_fs_writestream">#</a></span></h2>
<p><code>WriteStream</code> is a <a href="stream.html#stream_class_stream_writable">Writable Stream</a>.
</p>
<h3>Event: 'open'<span><a class="mark" href="#fs_event_open_1" id="fs_event_open_1">#</a></span></h3>
<div class="signature"><ul>
<li><code>fd</code> <span class="type">Integer</span> file descriptor used by the WriteStream.</li>
</div></ul>
<p>Emitted when the WriteStream's file is opened.
</p>
<h3>file.bytesWritten<span><a class="mark" href="#fs_file_byteswritten" id="fs_file_byteswritten">#</a></span></h3>
<p>The number of bytes written so far. Does not include data that is still queued
for writing.
</p>
<h2>Class: fs.FSWatcher<span><a class="mark" href="#fs_class_fs_fswatcher" id="fs_class_fs_fswatcher">#</a></span></h2>
<p>Objects returned from <code>fs.watch()</code> are of this type.
</p>
<h3>watcher.close()<span><a class="mark" href="#fs_watcher_close" id="fs_watcher_close">#</a></span></h3>
<p>Stop watching for changes on the given <code>fs.FSWatcher</code>.
</p>
<h3>Event: 'change'<span><a class="mark" href="#fs_event_change" id="fs_event_change">#</a></span></h3>
<div class="signature"><ul>
<li><code>event</code> <span class="type">String</span> The type of fs change</li>
<li><code>filename</code> <span class="type">String</span> The filename that changed (if relevant/available)</li>
</div></ul>
<p>Emitted when something changes in a watched directory or file.
See more details in <a href="#fs_fs_watch_filename_options_listener">fs.watch</a>.
</p>
<h3>Event: 'error'<span><a class="mark" href="#fs_event_error" id="fs_event_error">#</a></span></h3>
<div class="signature"><ul>
<li><code>error</code> <span class="type">Error object</span></li>
</div></ul>
<p>Emitted when an error occurs.
</p>
</div>
</div>
</div>
<div id="footer">
<a href="http://joyent.com" class="joyent-logo">Joyent</a>
<ul class="clearfix">
<li><a href="/">Node.js</a></li>
<li><a href="/download/">Download</a></li>
<li><a href="/about/">About</a></li>
<li><a href="http://npmjs.org/">npm Registry</a></li>
<li><a href="http://nodejs.org/api/">Docs</a></li>
<li><a href="http://blog.nodejs.org">Blog</a></li>
<li><a href="/community/">Community</a></li>
<li><a href="/logos/">Logos</a></li>
<li><a href="http://jobs.nodejs.org/">Jobs</a></li>
<li><a href="http://twitter.com/nodejs" class="twitter">@nodejs</a></li>
</ul>
<p>Copyright <a href="http://joyent.com/">Joyent, Inc</a>, Node.js is a <a href="/trademark-policy.pdf">trademark</a> of Joyent, Inc. View <a href="https://raw.github.com/joyent/node/v0.10.29/LICENSE">license</a>.</p>
</div>
<script src="../sh_main.js"></script>
<script src="../sh_javascript.min.js"></script>
<script>highlight(undefined, undefined, 'pre');</script>
<script>
window._gaq = [['_setAccount', 'UA-10874194-2'], ['_trackPageview']];
(function(d, t) {
var g = d.createElement(t),
s = d.getElementsByTagName(t)[0];
g.src = '//www.google-analytics.com/ga.js';
s.parentNode.insertBefore(g, s);
}(document, 'script'));
</script>
</body>
</html>
|
