link
(PHP 4, PHP 5)
link — Create a hard link
Description
bool link
( string
$target
, string $link
)link() creates a hard link.
Parameters
-
target -
Target of the link.
-
link -
The link name.
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | This function is now available on Windows platforms (Vista, Server 2008 or greater). |
Examples
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, $link);
?>
Notes
Note: This function will not work on remote files as the file to be examined must be accessible via the server's filesystem.
Note: For Windows only: This function requires PHP to run in an elevated mode or with the UAC disabled.
See Also
- symlink() - Creates a symbolic link
- readlink() - Returns the target of a symbolic link
- linkinfo() - Gets information about a link
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Коментарии
I noticed that, differently from Unix ln command, the second parameter can´t be a directory name, i.e., if you want to create a link with the same filename of the target file (obviously on different directories), you must specify the filename on the link parameter.
Example:
Unix ln command:
ln /dir1/file /dir2/ // ok, creates /dir2/file link
PHP link function:
link ("/dir1/file", "/dir2/"); // wrong, gives a "File exists" warning
link ("/dir1/file", "/dir2/file"); // ok, creates /dir2/file link
For a backup utility I needed link-like functionality on a windows system. As it isn't availible on windows, i tried to do it myself with the help of some tools. All you need is junction.exe from sysinternals in your %PATH%.
<?php
if(!function_exists('link')){ // Assume a windows system
function link($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.