stat

(PHP 4, PHP 5, PHP 7, PHP 8)

stat — Da informazioni su un file

Descrizione

stat(string $filename): array

Restituisce una serie di informazioni a riguardo del file filename. Se il parametro filename è un link simbolico, le informazioni riguardano il file stesso, e non il file puntato dal link. La funzione lstat() è identica a stat() tranne che dovrebbe restituire il file puntato dal link.

In caso di errore stat() restituisce false. Inoltre genera un warning.

La funzione restituisce un vettore con le informazioni sul file contenente i seguenti elementi. Il vettore parte dall'indice zero. Oltre agli indici numerici il vettore contiene indici associativi, come sarà indicato per ciascun parametro; questo è disponibile dal PHP versione 4.0.6.

**Formato del vettore restituito da **stat()** e fstat()**
Indice numerico	Associativo (da PHP 4.0.6)	Descrizione
0	dev	device
1	ino	inode
2	mode	modalità di protezione dell'inode
3	nlink	numero di link
4	uid	ID utente del proprietario
5	gid	ID del gruppo del proprietario
6	rdev	tipo di device con l'inode device *
7	size	dimensione in byte
8	atime	ora dell'ultimo accesso (Unix timestamp)
9	mtime	ora del'ultima modifica (Unix timestamp)
10	ctime	ora dell'ultimo cambiamento di inode(Unix timestamp)
11	blksize	dimensione del blocco per l'I/O di filesystem *
12	blocks	numero dei blocchi allocati

* - valida solo su sistemi che supportano il tipo st_blksize--altri sistemi (ad esempio Windows) restituiscono -1.

Nota: I risultati di questa funzione saranno memorizzati. Vedere clearstatcache() per maggiori dettagli.

Suggerimento

A partire da PHP 5.0.0, questa funzione può essere utilizzata con alcuni URL wrappers. Fare riferimento a Supported Protocols and Wrappers per la lista di quali wrappers supportano le funzioni della famiglia stat().

Vedere anche lstat(), fstat(), filemtime() e filegroup().

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User Contributed Notes 18 notes

down

webmaster at askapache dot com ¶

10 years ago


On GNU/Linux you can retrieve the number of currently running processes on the machine by doing a stat for hard links on the '/proc' directory like so:

$ stat -c '%h' /proc
118

You can do the same thing in php by doing a stat on /proc and grabbing the [3] 'nlink' - number of links in the returned array.

Here is the function I'm using, it does a clearstatcache() when called more than once.

<?php

/**
 * Returns the number of running processes
 *
 * @link http://php.net/clearstatcache
 * @link http://php.net/stat  Description of stat syntax.
 * @author http://www.askapache.com/php/get-number-running-proccesses.html
 * @return int
 */
function get_process_count() {
  static $ver, $runs = 0;
  
  // check if php version supports clearstatcache params, but only check once
  if ( is_null( $ver ) )
    $ver = version_compare( PHP_VERSION, '5.3.0', '>=' );
 
  // Only call clearstatcache() if function called more than once */
  if ( $runs++ > 0 ) { // checks if $runs > 0, then increments $runs by one.
    
    // if php version is >= 5.3.0
    if ( $ver ) {
      clearstatcache( true, '/proc' );
    } else {
      // if php version is < 5.3.0
      clearstatcache();
    }
  }
  
  $stat = stat( '/proc' );
 
  // if stat succeeds and nlink value is present return it, otherwise return 0
  return ( ( false !== $stat && isset( $stat[3] ) ) ? $stat[3] : 0 );
}

?>

Example #1 get_process_count() example

<?php
$num_procs = get_process_count();
var_dump( $num_procs );
?>

The above example will output:

int(118)

Which is the number of processes that were running.

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webmaster at askapache dot com ¶

15 years ago

down

admin at smitelli dot com ¶

19 years ago


There's an important (yet little-known) problem with file dates on Windows and Daylight Savings. This affects the 'atime' and 'mtime' elements returned by stat(), and it also affects other filesystem-related functions such as fileatime() and filemtime().

During the winter months (when Daylight Savings isn't in effect), Windows will report a certain timestamp for a given file. However, when summer comes and Daylight Savings starts, Windows will report a DIFFERENT timestamp! Even if the file hasn't been altered at all, Windows will shift every timestamp it reads forward one full hour during Daylight Savings.

This all stems from the fact that M$ decided to use a hackneyed method of tracking file dates to make sure there are no ambiguous times during the "repeated hour" when DST ends in October, maintain compatibility with older FAT partitions, etc. An excellent description of what/why this is can be found at http://www.codeproject.com/datetime/dstbugs.asp

This is noteworthy because *nix platforms don't have this problem. This could introduce some hard-to-track bugs if you're trying to move scripts that track file timestamps between platforms.

I spent a fair amount of time trying to debug one of my own scripts that was suffering from this problem. I was storing file modification times in a MySQL table, then using that information to see which files had been altered since the last run of the script. After each Daylight Savings change, every single file the script saw was considered "changed" since the last run, since all the timestamps were off by +/- 3600 seconds.

This one-liner is probably one of the most incorrect fixes that could ever be devised, but it's worked flawlessly in production-grade environments... Assuming $file_date is a Unix timestamp you've just read from a file:

<?php
    if (date('I') == 1) $file_date -= 3600;
?>

That will ensure that the timestamp you're working with is always consistently reported, regardless of whether the machine is in Daylight Savings or not.

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mao at nospam dot com ¶

19 years ago


If you have ftp (and the related sftp) protocols disabled on your remote server, it can be hard figuring out how to 'stat' a remote file. The following works for me:

<?php  

$conn = ssh2_connect($host, 22);
ssh2_auth_password($conn, $user, $password);
$stream = ssh2_exec($conn, "stat $fileName > $remotedest");
ssh2_scp_recv($conn, $remotedest, $localdest);
$farray = file($localdest);
print_r($farray);
?>

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salisbm at hotmail dot com ¶

21 years ago


I was curious how I could tell if a file was a directory... so I found on http://www.hmug.org/man/2/stat.html the following information about the mode bits:
#define S_IFMT 0170000           /* type of file */
#define        S_IFIFO  0010000  /* named pipe (fifo) */
#define        S_IFCHR  0020000  /* character special */
#define        S_IFDIR  0040000  /* directory */
#define        S_IFBLK  0060000  /* block special */
#define        S_IFREG  0100000  /* regular */
#define        S_IFLNK  0120000  /* symbolic link */
#define        S_IFSOCK 0140000  /* socket */
#define        S_IFWHT  0160000  /* whiteout */
#define S_ISUID 0004000  /* set user id on execution */
#define S_ISGID 0002000  /* set group id on execution */
#define S_ISVTX 0001000  /* save swapped text even after use */
#define S_IRUSR 0000400  /* read permission, owner */
#define S_IWUSR 0000200  /* write permission, owner */
#define S_IXUSR 0000100  /* execute/search permission, owner */

Note that these numbers are in octal format.  Then, to check to see if the file is a directory, after calling fstat, I do:

if ($fstats[mode] & 040000)
  ... this must be a directory

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ian at eiloart dot com ¶

25 years ago


Here's what the UNIX man page on stat has to say about the difference between a file change and  a file modification:



st_mtime  Time when data was last modified.  Changed by  the following  functions:   creat(),  mknod(), pipe(), utime(), and write(2).



st_ctime  Time when file status was last  changed.   Changed by  the  following  functions: chmod(), chown(), creat(), link(2), mknod(), pipe(), unlink(2), utime(), and write().



So a modification is a change in the data, whereas a change also happens if you modify file permissions and so on.

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digitalaudiorock at hotmail dot com ¶

15 years ago


Regarding the stat() on files larger than 2GB on 32 bit systems not working, note that the behavior appears to differ between Linux and Windows.  Under Windows there's so way to know whether or not this failed.

It's been my experience that under Linux, performing a stat() on files that are too large for the integer size generates a warning and returns false.  However under Windows it silently truncates the high order bits of the size resulting in an incorrect number.  The only way you'd ever know it failed is in the event that the truncation happened to leave the sign bit on resulting in a negative size.  That is, there is _no_ reliable way to know it failed.

This is true of filesize() as well.

Tom

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mail4rico at gmail dot com ¶

16 years ago


In response to the note whose first line is:
Re note posted by "admin at smitelli dot com"

I believe you have the conversion backwards. You should add an hour to filemtime if the system is in DST and the file is not. Conversely, you should subtract an hour if the file time is DST and the current OS time is not.

Here's a simplified, corrected version:
<?php
    function getmodtime($file) { //returns the time a file was modified.
        $mtime = filemtime($file);
        //date('I') returns 1 if DST is on and 0 if off.
        $diff = date('I')-date('I', $mtime);
        //diff =  0 if file-time and os-time are both in the same DST setting
        //diff =  1 if os is DST and file is not
        //diff = -1 if file is DST and os is not
        return $mtime + $diff*3600;
    }
?>
Here's a test:
<?php
    //create two dummy files:
    $file0 = 'file1.txt';
    $file1 = 'file2.txt';
    file_put_contents($file0, '');
    file_put_contents($file1, '');
    
    $time0=strtotime('Jan 1 2008 10:00'); echo 'Date0 (ST): ' . date(DATE_COOKIE, $time0)."\n";
    $time1=strtotime('Aug 1 2008 10:00'); echo 'Date1 (DT): ' . date(DATE_COOKIE, $time1)."\n";
    touch($file0, $time0); //set file0 to Winter (Non-DST)
    touch($file1, $time1); //set file1 to Summer (DST)
    
    $ftime0 = filemtime($file0);
    $ftime1 = filemtime($file1);
    echo "\nUncorrected: \n";
    echo 'File 0: ' . ($ftime0-$time0) ."\n";
    echo 'File 1: ' . ($ftime1-$time1) ."\n";
    //if your system adjusts for DST, then _one_ of the above should be 3600 or -3600, depending on the time of year
    
    $ftime0 = getmodtime($file0); //use filemtime correction
    $ftime1 = getmodtime($file1); //use filemtime correction
    echo "\nCorrected: \n";
    echo 'File 0: ' . ($ftime0-$time0) ."\n";
    echo 'File 1: ' . ($ftime1-$time1) ."\n";
    //both of the corrected values output should be 0.
?>

Output:
------------------------------
(when run in summer)
------------------------------
Date0 (ST): Tuesday, 01-Jan-08 10:00:00 EST
Date1 (DT): Friday, 01-Aug-08 10:00:00 EDT

Uncorrected: 
File 0: -3600
File 1: 0

Corrected: 
File 0: 0
File 1: 0
------------------------------
(when run in winter--dates omitted)
------------------------------
Uncorrected: 
File 0: 0
File 1: 3600

Corrected: 
File 0: 0
File 1: 0

In response to Re note posted by "admin at smitelli dot com",  your version below gives the following output when substituted into my test:
------------------------------
(when run in summer--dates omitted)
------------------------------
Uncorrected: 
File 0: -3600
File 1: 0

Corrected: 
File 0: -7200
File 1: 0
------------------------------
You can see that the operation is the opposite of what it should be.

down

com dot gmail at algofoogle ¶

19 years ago


Re note posted by "salisbm at hotmail dot com":

S_IFDIR is not a single-bit flag. It is a constant that relies on the "S_IFMT" bitmask. This bitmask should be applied to the "mode" parameter before comparing with any of the other "S_IF..." constants, as indicated by stat.h:

#define S_ISDIR(m)  (((m) & S_IFMT) == S_IFDIR)

That is, this approach is incorrect:

<?php
define('S_IFDIR',040000);
if ($mode & S_IFDIR)
{
  /*
    incorrect!
    format could be S_IFDIR, but also
    S_IFBLK, S_IFSOCK, or S_IFWHT.
  */
}
?>

...and should instead be:

<?php
define('S_IFMT',0170000);
define('S_IFDIR',040000);
if (S_IFDIR == ($mode & S_IFMT)) {  /* ... */  }
?>

As pointed out by "svend at svendtofte dot com", however, there is also the "is_dir" function for this purpose, along with "is_file" and "is_link" to cover the most common format types...

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marting.dc AT gmail.com ¶

18 years ago


If you want to know a directory size, this function will help you:



<?php

function dir_size($dir)

{

    $handle = opendir($dir);

    

    while ($file = readdir($handle)) {

        if ($file != '..' && $file != '.' && !is_dir($dir.'/'.$file)) {

            $mas += filesize($dir.'/'.$file);

            } else if (is_dir($dir.'/'.$file) && $file != '..' && $file != '.') {

            $mas += dir_size($dir.'/'.$file);

        }

    }

    return $mas;

}

echo dir_size('DIRECTORIO').' Bytes';

?>

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JulieC ¶

17 years ago


The dir_size function provided by "marting.dc AT gmail.com" works great, except the $mas variable is not initialized.  Add:

   $mas = 0;

before the while() loop.

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svend at svendtofte dot com ¶

20 years ago


To the note of how you can figure out if a file is a folder or not, there is also the handy "is_dir" function.

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Hellhound ¶

16 years ago


To ignore index number or name specifics.. use:

list($dev, $ino, $mode, $nlink, $uid, $gid, $rdev, $size, $atime, $mtime, $ctime, $blksize, $blocks)
         = lstat($directory_element);

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carlos [at] encore-lab [dot] com ¶

10 years ago


stat() may not work on mounted CIFS' in 32 bit systems if you do not specify the option noserverino when mounting. E.g:

mount -t cifs -o user="user",password="password",noserverino //example.local/share /mnt/mount-point

Other functions based on stat() data such as file time functions and is_dir() are affected the same way.

This happens because if you do not specify the option noserverino the remote inode may be 64 bit-based and thus the local system cannot handle it.

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Ray.Paseur sometimes uses Gmail ¶

3 years ago


A good explanation of the "mode" bits is given here:
https://www.php.net/manual/en/function.fileperms.php

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Anonymous ¶

18 years ago


Re note posted by "admin at smitelli dot com"

I'm not sure how that can work all year round since you have to modify both opposing inside and outside DST based on the actual files themselves, as well as the current DST setting for the system.

e.g. using filemtime, same thing for stat.

<?php

$mtime = filemtime($file);

if (date('I') == 1) {
    // Win DST is enabled, adjust standard time 
    // files back to 'real' file UTC.
    if (date('I', $mtime) == 0) {
        $mtime -= 3600;
    }
} else {
    // Win DST is disabled, adjust daylight time 
    // files forward to 'real' file UTC.
    if (date('I', $mtime) == 1) {
        $mtime += 3600;
    }
}

echo gmdate('Y-m-d H:i:s', $mtime);

?>

Just another example of why 'not' to use windows in a server room.

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-2

antonixyz at gmx dot net ¶

16 years ago


<?php

$stat = stat($filepath);

$mode = $stat[2];

?>

is identical to:

<?php $mode = fileperms($filepath); ?>



at least on my linux box.

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-3

Anonymous ¶

20 years ago


If the 2GB limit is driving you crazy, you can use this complete hack.  use in place of filesize()

function file_size($file) {
  $size = filesize($file);
  if ( $size == 0)
    $size = exec("ls -l $file | awk '{print $5}'");
  return $size;
}

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