Curl - upload multiple attachment arrays to server webpage

The html page of the form data is as below

<form name="uploadform" id="uploadform" action="htmlupload.php" enctype="multipart/form-data" method="post">  <table class="tborder" cellpadding="6" cellspacing="1" border="0" width="100%" align="center"> <tr>     <td class="tcat">         Upload Files     </td> </tr> <tr>     <td class="panelsurround" align="center">     <div id="upload" class="panel">         <div style="width:720px" align="left">             <table border="0"><tr>                 <td>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                 </td>                 <td>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                 </td>                 <td>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                     <div><input name="attachment[]" type="file"></div>                 </td>             </tr></table>         </div>         <div style="margin-top:6px">             <input value="6ece14a18366a322c347c71cbfe87420" name="uploadcode" type="hidden" />             <input value="upload" name="do" type="hidden" />             <input value="upload" name="uploadbutton" onclick="onClickVerify();" class="button" type="button" accesskey="s" />             <input type="reset" class="button" value="Reset Fields" accesskey="r" />         </div>     </div>     <div class="panel" id="status" style="display:none;width:100%;">         �     </div>     </td> </tr> </table>  </form>

I am trying to post files and upload using the curl command, tried the below two commands

curl -b cookie.txt -d "attachment[]=@1.png&do=upload" http://f7.masaladesi.com/htmlupload.php curl -b cookie.txt -F "attachment[]=@1.png" http://f7.masaladesi.com/htmlupload.php

The image of the webpage(public one if you are registered)

Please give me a hint on how to achieve this, it is an array of selecting the attachments

---------- Post updated at 10:37 AM ---------- Previous update was at 06:25 AM ----------

Tried with the below command

curl -b cookie.txt --form "attachment[]=@1.png" --form "do=upload" myurl

But it says "invalid upload" in the resulting webpage. That means the upload button works, something wrong while sending the attachment

---------- Post updated at 10:41 AM ---------- Previous update was at 10:37 AM ----------

Also the webpage is a forum, it is same as clicking on "Manage Attachments" button after create a new thread. You will see an array of Browse button with an ' upload' at the end