How to use strpos to determine if a string exists in input string?

Question

$filename = \'my_upgrade(1).zip\';
$match = \'my_upgrade\';

if(!strpos($filename, $match))
    {
    die();
    }
else 
   {
   //proceed
   }

In

Answer 1

This working for me when everything other fail in some situations:

$filename = 'my_upgrade(1).zip';
$match = 'my_upgrade';
$checker == false;
if(strpos($filename, $match))
    {
    $checker == true;
    }
if ($checker === false)
{ 
die();
}
else 
{
//proceed
}

Or in short:

$filename = 'my_upgrade(1).zip';
$match = 'my_upgrade';
$checker == false;
if(strpos($filename, $match))
    {
    $checker == true;
//proceed
 }
if ($checker === false)
{ 
die();
}