touch

(PHP 4, PHP 5)

touch — Nastaví pre súbor čas posledného prístupu a modifikácie

Popis

int touch ( string $nazovsuboru [, int $cas [, int $pcas ]] )

Pokúsi sa zmeniť čas posledného prístupu a modifikácie pre súbor zadaný v parametri nazovsuboru na hodnotu zadanú časom. Ak nie je zadaný parameter cas , použije sa aktuálny. To je ekvivalentné tomu, čo vykonáva utime (niekedy označovaný ako utimes). Ak je špecifikovaná aj tretia možnosť pcas , čas posledného prístupu (access time) k súboru je nastavený na hodnotu danú týmto parametrom pcas . Všimnite si, že čas posledného prístupu bude zmenený vždy, bez ohľadu na počet parametrov.

Ak súbor neexistuje, bude vytvorený.

Vracia TRUE pri úspechu alebe FALSE pri chybe.

Example#1 Príklad na touch()


if (touch ($FileName)) {
    print "Čas poslednej modifikácie súboru $FileName bol
           zmenený na dnešný dátum a čas";
} else {
    print "Chyba: nemožno zmeniť dátum poslednej modifikácie súboru $FileName";
}

umask

tmpfile

Last updated: Sun, 25 Nov 2007

add a note User Contributed Notes
touch

Bess E. R. Wisser
25-Aug-2008 01:20


"Glen: In unix on the command-line, you can touch files you don't own - but like other comments on this page state - PHP's built in touch won't work."



No, you can not modify files you don't have write access to in a multi-user environment, ever, under any circumstances. The reason why you fail to do this "in PHP" is because your httpd is most likely running as a "shared" setup, running as nobody/nobody, and your user's files aren't world-writable, and they are not owned by nobody/nobody. Change your required files to be world-writable and you can touch() them, and more.

Radon8472
08-Aug-2008 05:07


Important info:



touch() used on a directory always returns FALSE and prints "Permission denied" on NTFS and FAT Filesystem (tested on winXP).

Jeff
26-Jun-2008 12:29


I've been trying to set a filemtime into the future with touch() on PHP5.



It seems touch $time has a future limit around 1000000 seconds (11 days or so). Beyond this point it reverts to a previous $time.



It doesn't make much sense but I could save you hours of time.



$time = time()+1500000;

touch($cachedfile,$time);

Glen
18-Oct-2007 01:01


In unix on the command-line, you can touch files you don't own - but like other comments on this page state - PHP's built in touch won't work.



I simple alternative (on unix):



<?php



    function touch_it_good($filename)

    {

        exec("touch {$filename}");

    }

?>

ilrazziatore85 AT yahoo DOT it
21-May-2007 08:10


Feathern wrote a little script for fetching files from a directory after a certain date.

However the if statement (line 8) should be:



if(($test[2] > 2002) || (($test[2] = 2002) && ($test[0] > 6)) || (($test[2] = 2002) && ($test[0] = 6) && ($test[1] > 17))){

        echo $filelist[$i]."\r\n";

}



Otherwise the script won't fetch lots of files it should.



(In the example given, it should fetch all the files created after 06/17/2002, but the original script would miss files created 03/18/2003 or 11/01/2004)

seocab at rit dot edu
31-Mar-2007 09:09


The script for modifying the access time without modifying the modified time is overly complicated:



<? touch($filename, date('U', filemtime($filename)), time()); ?>



Since filemtime returns a UNIX timestamp, there is no need to call date('U') so the script could be simplified to:



<? touch($filename,filemtime($filename),time()); ?>

Charles Belov
18-Jul-2006 06:10


Update the access time without updating the modified time:



Unix command: touch -a filename



PHP: touch(filename, date('U', filemtime(filename)), time())

spam at webmastersguide dot com
01-Sep-2005 05:09


If you're going to go around deleting (unlinking) files

that you don't own just in order to change the modification

time on the file, you darn well better chown() the file 

back to it's original ownership after you are done and

chmod() it back to it's correct permissions.  Otherwise 

you will almost certainly break things.  Additionally the

code listed for touch()ing a file you don't own should 

set the file creation time back to it's original time if 

what is wanted is to just change the modification time.

Also, the code listed will break things if there is an i/o 

error such as disk full or too many files in the directory.

Here's how the code SHOULD be written:



Create the new file FIRST, rather than last, with a different

name such as $file.tmp.

Read the ownership, permissions, and creation time of the old file.

Set permissions and creation time of the new file the same as the old.

Rename the new file to the name of the old.

chown() the new file to the user that owned the file it's replacing.



Please be careful adding to the documentation if you've 

never taken programming 101.

rf_public at yahoo dot co dot uk
25-Jul-2005 12:19


Note: the script to touch a file you don't own will change it's owner so ensure permissions are correct or you could lose access to it

guy at forster design dot com
12-May-2005 03:42


Here's a little workaround that allows the PHP user to touch a file it doesn't own:



<?php



    $target_file = "/path/to/file/filename.txt"; //system filepath to your file

    $file_content = implode("",file($target_file));

    @unlink($target_file);

    if($savetofile = fopen($target_file, "w")) {

        fputs($savetofile, $file_content);

        fclose($savetofile);

    }

    $new_date = strtotime("23 April 2005"); // set the required date timestamp here

    touch($target_file,$new_date);

 

?>



Of course, PHP needs to have write access to the folder containing the file you want to touch, but that should be easy to arrange.

feathern at yahoo dot com
13-Aug-2002 03:31


Neat little script that will give you a list of all modified files in a certain folder after a certain date:



$filelist = Array();

$filelist = list_dir("d:\\my_folder");

for($i=0;$i<count($filelist);$i++){

    $test = Array();

    $test = explode("/",date("m/d/Y",filemtime($filelist[$i])));

//example of files that are later then

//06/17/2002

    if(($test[2] > 2001) && ($test[1] > 16) && ($test[0] > 5)){

        echo $filelist[$i]."\r\n";

    }

    clearstatcache();

}

function list_dir($dn){

    if($dn[strlen($dn)-1] != '\\') $dn.='\\';

    static $ra = array();

    $handle = opendir($dn);

    while($fn = readdir($handle)){

        if($fn == '.' || $fn == '..') continue;

        if(is_dir($dn.$fn)) list_dir($dn.$fn.'\\');

        else $ra[] = $dn.$fn;

    }

    closedir($handle);

    return $ra;

}

emilebosch at hotmail dot com
06-Oct-2001 03:41


To spare you ppl couple of hours of valuable time, you can only TOUCH a file that you own! Usually PHP is *nobody* 


Warm regards,


Emile Bosch

master at dreamphp dot com
15-May-2001 11:23


$filename = "test.dat";


if (!file_exists($filename)) {


  touch($filename); // Create blank file


  chmod($filename,0666);


}

add a note

umask

tmpfile

Last updated: Sun, 25 Nov 2007