PHP changes the code of all file suffixes in the directory and subdirectories_PHP tutorial

//This file and the directory to be changed Put the files in the same folder
define("STA",".gif");//The original file format
define("END",".jpg");//The format to be changed
$dir="./";
$arr=allfile($dir);
foreach($arr as $t)
{
$t=str_replace(".//" ,"",$t);
if(substr_count($t,STA)>0)
{
$f2=str_replace(STA,"",$t);
rename( $t,$f2.END);
}
}
//Function to get all files in the directory
function allfile($dir)
{
$files=array( );
if(is_file($dir))
{
return $dir;
}
$handle = opendir($dir);
if($handle) {
while(false !== ($file = readdir($handle))) {
if ($file != '.' && $file != '..') {
$filename = $ dir . "/" . $file;
if(is_file($filename)) {
$files[] = $filename;
}else {
$files = array_merge($files, allfile ($filename));
}
}
} // end while
closedir($handle);
}
return $files;
}

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