2 .\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992
3 .\" Parts Copyright (c) 1995 Nicolai Langfeldt (janl@ifi.uio.no), 1/1/95
4 .\" and Copyright (c) 2007 Michael Kerrisk <mtk.manpages@gmail.com>
6 .\" %%%LICENSE_START(VERBATIM)
7 .\" Permission is granted to make and distribute verbatim copies of this
8 .\" manual provided the copyright notice and this permission notice are
9 .\" preserved on all copies.
11 .\" Permission is granted to copy and distribute modified versions of this
12 .\" manual under the conditions for verbatim copying, provided that the
13 .\" entire resulting derived work is distributed under the terms of a
14 .\" permission notice identical to this one.
16 .\" Since the Linux kernel and libraries are constantly changing, this
17 .\" manual page may be incorrect or out-of-date. The author(s) assume no
18 .\" responsibility for errors or omissions, or for damages resulting from
19 .\" the use of the information contained herein. The author(s) may not
20 .\" have taken the same level of care in the production of this manual,
21 .\" which is licensed free of charge, as they might when working
24 .\" Formatted or processed versions of this manual, if unaccompanied by
25 .\" the source, must acknowledge the copyright and authors of this work.
28 .\" Modified by Michael Haardt <michael@moria.de>
29 .\" Modified 1993-07-24 by Rik Faith <faith@cs.unc.edu>
30 .\" Modified 1995-05-18 by Todd Larason <jtl@molehill.org>
31 .\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
32 .\" Modified 1995-01-09 by Richard Kettlewell <richard@greenend.org.uk>
33 .\" Modified 1998-05-13 by Michael Haardt <michael@cantor.informatik.rwth-aachen.de>
34 .\" Modified 1999-07-06 by aeb & Albert Cahalan
35 .\" Modified 2000-01-07 by aeb
36 .\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
37 .\" 2007-06-08 mtk: Added example program
38 .\" 2007-07-05 mtk: Added details on underlying system call interfaces
40 .TH STAT 2 2012-11-11 "Linux" "Linux Programmer's Manual"
42 stat, fstat, lstat \- get file status
44 .B #include <sys/types.h>
46 .B #include <sys/stat.h>
48 .B #include <unistd.h>
50 .BI "int stat(const char *" path ", struct stat *" buf );
52 .BI "int fstat(int " fd ", struct stat *" buf );
54 .BI "int lstat(const char *" path ", struct stat *" buf );
57 Feature Test Macro Requirements for glibc (see
58 .BR feature_test_macros (7)):
65 _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
66 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
68 || /* Since glibc 2.10: */ _POSIX_C_SOURCE\ >=\ 200112L
74 These functions return information about a file.
75 No permissions are required on the file itself, but\(emin the case of
80 execute (search) permission is required on all of the directories in
82 that lead to the file.
85 stats the file pointed to by
95 is a symbolic link, then the link itself is stat-ed,
96 not the file that it refers to.
101 except that the file to be stat-ed is specified by the file descriptor
104 All of these system calls return a
106 structure, which contains the following fields:
111 dev_t st_dev; /* ID of device containing file */
112 ino_t st_ino; /* inode number */
113 mode_t st_mode; /* protection */
114 nlink_t st_nlink; /* number of hard links */
115 uid_t st_uid; /* user ID of owner */
116 gid_t st_gid; /* group ID of owner */
117 dev_t st_rdev; /* device ID (if special file) */
118 off_t st_size; /* total size, in bytes */
119 blksize_t st_blksize; /* blocksize for file system I/O */
120 blkcnt_t st_blocks; /* number of 512B blocks allocated */
121 time_t st_atime; /* time of last access */
122 time_t st_mtime; /* time of last modification */
123 time_t st_ctime; /* time of last status change */
130 field describes the device on which this file resides.
135 macros may be useful to decompose the device ID in this field.)
139 field describes the device that this file (inode) represents.
143 field gives the size of the file (if it is a regular
144 file or a symbolic link) in bytes.
145 The size of a symbolic link is the length of the pathname
146 it contains, without a terminating null byte.
150 field indicates the number of blocks allocated to the file, 512-byte units.
151 (This may be smaller than
153 when the file has holes.)
157 field gives the "preferred" blocksize for efficient file system I/O.
158 (Writing to a file in smaller chunks may cause
159 an inefficient read-modify-rewrite.)
161 Not all of the Linux file systems implement all of the time fields.
162 Some file system types allow mounting in such a way that file
163 and/or directory accesses do not cause an update of the
173 and related information in
177 is not updated if a file is opened with the
184 is changed by file accesses, for example, by
191 (of more than zero bytes).
194 may or may not update
199 is changed by file modifications, for example, by
205 (of more than zero bytes).
208 of a directory is changed by the creation or deletion of files
214 changed for changes in owner, group, hard link count, or mode.
218 is changed by writing or by setting inode information
219 (i.e., owner, group, link count, mode, etc.).
221 The following POSIX macros are defined to check the file type using the
227 is it a regular file?
242 symbolic link? (Not in POSIX.1-1996.)
245 socket? (Not in POSIX.1-1996.)
248 The following flags are defined for the
254 S_IFMT 0170000 bit mask for the file type bit fields
255 S_IFSOCK 0140000 socket
256 S_IFLNK 0120000 symbolic link
257 S_IFREG 0100000 regular file
258 S_IFBLK 0060000 block device
259 S_IFDIR 0040000 directory
260 S_IFCHR 0020000 character device
262 S_ISUID 0004000 set-user-ID bit
263 S_ISGID 0002000 set-group-ID bit (see below)
264 S_ISVTX 0001000 sticky bit (see below)
265 S_IRWXU 00700 mask for file owner permissions
266 S_IRUSR 00400 owner has read permission
267 S_IWUSR 00200 owner has write permission
268 S_IXUSR 00100 owner has execute permission
269 S_IRWXG 00070 mask for group permissions
270 S_IRGRP 00040 group has read permission
271 S_IWGRP 00020 group has write permission
272 S_IXGRP 00010 group has execute permission
273 S_IRWXO 00007 mask for permissions for others (not in group)
274 S_IROTH 00004 others have read permission
275 S_IWOTH 00002 others have write permission
276 S_IXOTH 00001 others have execute permission
282 has several special uses.
283 For a directory it indicates that BSD semantics is to be used
284 for that directory: files created there inherit their group ID from
285 the directory, not from the effective group ID of the creating process,
286 and directories created there will also get the
289 For a file that does not have the group execution bit
292 the set-group-ID bit indicates mandatory file/record locking.
296 on a directory means that a file
297 in that directory can be renamed or deleted only by the owner
298 of the file, by the owner of the directory, and by a privileged
301 On success, zero is returned.
302 On error, \-1 is returned, and
304 is set appropriately.
308 Search permission is denied for one of the directories
309 in the path prefix of
312 .BR path_resolution (7).)
322 Too many symbolic links encountered while traversing the path.
336 Out of memory (i.e., kernel memory).
339 A component of the path prefix of
347 refers to a file whose size, inode number,
348 or number of blocks cannot be represented in, respectively, the types
353 This error can occur when, for example,
354 an application compiled on a 32-bit platform without
355 .I -D_FILE_OFFSET_BITS=64
358 on a file whose size exceeds
362 These system calls conform to SVr4, 4.3BSD, POSIX.1-2001.
363 .\" SVr4 documents additional
365 .\" error conditions EINTR, ENOLINK, and EOVERFLOW. SVr4
366 .\" documents additional
370 .\" error conditions EINTR, EMULTIHOP, ENOLINK, and EOVERFLOW.
372 According to POSIX.1-2001,
374 on a symbolic link need return valid information only in the
376 field and the file-type component of the
381 POSIX.-2008 tightens the specification, requiring
383 to return valid information in all fields except the permission bits in
390 fields may be less portable.
391 (They were introduced in BSD.
392 The interpretation differs between systems,
393 and possibly on a single system when NFS mounts are involved.)
394 If you need to obtain the definition of the
402 with the value 500 or greater (before including
406 POSIX.1-1990 did not describe the
416 constants, but instead demanded the use of
422 constants are present in POSIX.1-2001 and later.
429 POSIX.1-1996, but both are present in POSIX.1-2001;
430 the former is from SVID 4, the latter from SUSv2.
432 UNIX V7 (and later systems) had
437 prescribes the synonyms
442 Values that have been (or are) in use on various systems:
446 hex name ls octal description
447 f000 S_IFMT 170000 mask for file type
449 SCO out-of-service inode; BSD unknown type; SVID-v2 and XPG2
450 have both 0 and 0100000 for ordinary file
452 1000 S_IFIFO p| 010000 FIFO (named pipe)
453 2000 S_IFCHR c 020000 character special (V7)
454 3000 S_IFMPC 030000 multiplexed character special (V7)
455 4000 S_IFDIR d/ 040000 directory (V7)
456 5000 S_IFNAM 050000 T{
457 XENIX named special file with two subtypes, distinguished by
458 \fIst_rdev\fP values 1, 2
460 0001 S_INSEM s 000001 XENIX semaphore subtype of IFNAM
461 0002 S_INSHD m 000002 XENIX shared data subtype of IFNAM
462 6000 S_IFBLK b 060000 block special (V7)
463 7000 S_IFMPB 070000 multiplexed block special (V7)
464 8000 S_IFREG - 100000 regular (V7)
465 9000 S_IFCMP 110000 VxFS compressed
466 9000 S_IFNWK n 110000 network special (HP-UX)
467 a000 S_IFLNK l@ 120000 symbolic link (BSD)
468 b000 S_IFSHAD 130000 T{
469 Solaris shadow inode for ACL (not seen by user space)
471 c000 S_IFSOCK s= 140000 socket (BSD; also "S_IFSOC" on VxFS)
472 d000 S_IFDOOR D> 150000 Solaris door
473 e000 S_IFWHT w% 160000 BSD whiteout (not used for inode)
474 0200 S_ISVTX 001000 T{
475 sticky bit: save swapped text even after use (V7)
479 On nondirectories: don't cache this file (SunOS)
481 On directories: restricted deletion flag (SVID-v4.2)
483 0400 S_ISGID 002000 T{
484 set-group-ID on execution (V7)
486 for directories: use BSD semantics for propagation of GID
488 0400 S_ENFMT 002000 T{
489 System V file locking enforcement (shared with S_ISGID)
491 0800 S_ISUID 004000 set-user-ID on execution (V7)
493 directory is a context dependent file (HP-UX)
498 A sticky command appeared in Version 32V AT&T UNIX.
500 Since kernel 2.5.48, the
502 structure supports nanosecond resolution for the three file timestamp fields.
503 Glibc exposes the nanosecond component of each field using names of the form
509 feature test macro is defined.
510 These fields are specified in POSIX.1-2008, and, starting with version 2.12,
511 glibc also exposes these field names if
513 is defined with the value 200809L or greater, or
515 is defined with the value 700 or greater.
516 If none of the aforementioned macros are defined,
517 then the nanosecond values are exposed with names of the form
519 On file systems that do not support subsecond timestamps,
520 the nanosecond fields are returned with the value 0.
521 .\" As at kernel 2.6.25, XFS and JFS support nanosecond timestamps,
522 .\" but ext2, ext3, and Reiserfs do not.
526 will generally not trigger automounter action, whereas
531 For most files under the
535 does not return the file size in the
537 field; instead the field is returned with the value 0.
538 .SS Underlying kernel interface
539 Over time, increases in the size of the
541 structure have led to three successive versions of
551 (new in kernel 2.4; slot
555 wrapper function hides these details from applications,
556 invoking the most recent version of the system call provided by the kernel,
557 and repacking the returned information if required for old binaries.
558 Similar remarks apply for
563 .\" A note from Andries Brouwer, July 2007
565 .\" > Is the story not rather more complicated for some calls like
568 .\" Yes and no, mostly no. See /usr/include/sys/stat.h .
570 .\" The idea is here not so much that syscalls change, but that
571 .\" the definitions of struct stat and of the types dev_t and mode_t change.
572 .\" This means that libc (even if it does not call the kernel
573 .\" but only calls some internal function) must know what the
574 .\" format of dev_t or of struct stat is.
575 .\" The communication between the application and libc goes via
576 .\" the include file <sys/stat.h> that defines a _STAT_VER and
577 .\" _MKNOD_VER describing the layout of the data that user space
578 .\" uses. Each (almost each) occurrence of stat() is replaced by
579 .\" an occurrence of xstat() where the first parameter of xstat()
580 .\" is this version number _STAT_VER.
582 .\" Now, also the definitions used by the kernel change.
583 .\" But glibc copes with this in the standard way, and the
584 .\" struct stat as returned by the kernel is repacked into
585 .\" the struct stat as expected by the application.
586 .\" Thus, _STAT_VER and this setup cater for the application-libc
587 .\" interface, rather than the libc-kernel interface.
589 .\" (Note that the details depend on gcc being used as c compiler.)
591 The following program calls
593 and displays selected fields in the returned
598 #include <sys/types.h>
599 #include <sys/stat.h>
605 main(int argc, char *argv[])
610 fprintf(stderr, "Usage: %s <pathname>\\n", argv[0]);
614 if (stat(argv[1], &sb) == \-1) {
619 printf("File type: ");
621 switch (sb.st_mode & S_IFMT) {
622 case S_IFBLK: printf("block device\\n"); break;
623 case S_IFCHR: printf("character device\\n"); break;
624 case S_IFDIR: printf("directory\\n"); break;
625 case S_IFIFO: printf("FIFO/pipe\\n"); break;
626 case S_IFLNK: printf("symlink\\n"); break;
627 case S_IFREG: printf("regular file\\n"); break;
628 case S_IFSOCK: printf("socket\\n"); break;
629 default: printf("unknown?\\n"); break;
632 printf("I\-node number: %ld\\n", (long) sb.st_ino);
634 printf("Mode: %lo (octal)\\n",
635 (unsigned long) sb.st_mode);
637 printf("Link count: %ld\\n", (long) sb.st_nlink);
638 printf("Ownership: UID=%ld GID=%ld\\n",
639 (long) sb.st_uid, (long) sb.st_gid);
641 printf("Preferred I/O block size: %ld bytes\\n",
642 (long) sb.st_blksize);
643 printf("File size: %lld bytes\\n",
644 (long long) sb.st_size);
645 printf("Blocks allocated: %lld\\n",
646 (long long) sb.st_blocks);
648 printf("Last status change: %s", ctime(&sb.st_ctime));
649 printf("Last file access: %s", ctime(&sb.st_atime));
650 printf("Last file modification: %s", ctime(&sb.st_mtime));
662 .BR capabilities (7),