Parse Iperf CSV Data

iperf_parse.php

<?php

	function convert_bytes($bytes)
	{
	      if($bytes >= 1048576)
	      {
		  $megabytes = round(($bytes/(1000*1000)),2);
		  return $megabytes;
	      }
	      else
	      {
		  $kilobytes = round(($bytes/1000),2);
		  return $kilobytes; 
	      }
	}

	if(array_key_exists(2,$argv))
	{
		$filename = $argv[1];
	}
	else
	{	
		echo "Usage \"php parse.php inputfilename outputfilename\"\n";	
	}
	if(isset($filename))
	{	
		if (file_exists($filename)) 
		{
 			$file_contents = file_get_contents($filename);
			$chunks = explode(",", $file_contents);
			$count = 16;
			echo "\n";
			$output = '';
			
			while($count < sizeof($chunks))
			{
				 
				$output = $output.convert_bytes($chunks[$count]).",";
				$count += 21;
			}
		
			file_put_contents($argv[2],$output);
		} 
		else 
		{
    			echo "The file $filename does not exist\n";
		}
	}
?>