PHP implements the method of batch modifying file suffix name

/**
  * Bulk modification of file suffix name
  * @param $path folder path
  * @param $sext Original file suffix name ($sext=all indicates all files in the entire directory)
  * @param $dext Destination file suffix name
  * @return void
  */
function foreachDir($path,$sext,$dext){ 
  $handle=opendir($path); 
  if($handle){ 
  while (false !== ($file = readdir($handle))) { 
   if($file!="." && $file!='..'){ 
    if(is_dir($path.$file)){ 
     foreachDir($path.$file); 
    }else{ 
     $ext = strripos($file,'.'); 
     $fileName = substr($file,0,$ext); 
     $src = $path.'/'.$file;
     $dest = $path.'/'.$fileName.'.'.$dext;
     if($sext!="all"){
      if($sext == substr($src,0-strlen($sext))) rename($src,$dest); 
     }else{
      rename($src,$dest); 
     }
    } 
   } 
  } 
   return false; 
  } 
}
foreachDir('C:\Users\chenlinzhong\Desktop\redis-stable\src','c','txt');