dump Mysql tables in centos server by using php code ...?

Question

I am running one application in centos server.

I am trying to make dumping(BackUp) one table to folder

1st Example :

<?php
  $cmd = "passwd";
  echo exec($cmd,$arr);
  print_r($arr);
?>

Output is :

 Changing password for apache.
 Array
(
     [0] => Changing password for user apache.
     [1] => Changing password for apache.
)

But While using mysqldump command i am getting empty array as a result

<?php
  $cmd = "mysqldump -u root db_name table_name > /var/path/file.csv";
  echo exec($cmd,$arr);
  print_r($arr);
?>

Output:

Array()

Thanks

Answer 1

 <?PHP
 $cmd = "mysqldump -u root db_name table_name > /var/path/filename.sql";
 echo shell_exec($cmd);
 ?>

Answer 2

Might be password issue. Please try following code:

 <?PHP
 $cmd = "mysqldump --u root --p password db_name table_name > /var/path/filename.sql";
 echo shell_exec($cmd);
 ?>