(PHP 4, PHP 5, PHP 7, PHP 8)
link — Create a hard link
targetTarget of the link.
linkThe link name.
The function fails, and issues E_WARNING , if link
already exists, or if target does not exist.
Example #1 Creating a simple hard link
<?php
$target = 'source.ext'; // This is the file that already exists
$link = 'newfile.ext'; // This the filename that you want to link it to
link($target, $link);
?>Note: This function will not work on remote files as the file to be examined must be accessible via the server's filesystem.
Note: For Windows only: This function requires PHP to run in an elevated mode or with the UAC disabled.
For a backup utility I needed link-like functionality on a windows system. As it isn't availible on windows, i tried to do it myself with the help of some tools. All you need is junction.exe from sysinternals in your %PATH%.
<?php
if(!function_exists('link')){ // Assume a windows system
function link($target, $link){
if(is_dir($target)){
// junctions link to directories in windows
exec("junction $link$target", $lines, $val);
return 0 == $val;
}elseif(is_file($target)){
// Hardlinks link to files in windows
exec("fsutil hardlink create $link$target", $lines, $val);
return 0 == $val;
}
return false;
}
}
?>
http://www.sysinternals.com/Utilities/Junction.html to clarify:
in unix/linux:
hardlinks (by this function) cannot go across different filesystems.
softlinks can point anywhere.
in linux, hardlinking to directory is not permited.I noticed that, differently from Unix ln command, the second parameter can ́t be a directory name, i.e., if you want to create a link with the same filename of the target file (obviously on different directories), you must specify the filename on the link parameter.
Example:
Unix ln command:
ln /dir1/file /dir2/ // ok, creates /dir2/file link
PHP link function:
link ("/dir1/file", "/dir2/"); // wrong, gives a "File exists" warning
link ("/dir1/file", "/dir2/file"); // ok, creates /dir2/file link