[Lesane]

It adds the output to $rosterbits and don't overwrite the current value of $rosterbits. If you leave the period out of it then $rosterbits will only contains one output. It does the while loop and adds a value to $rosterbits till it's done but it overwrites it without the period.

Same like:

PHP Code:

$hello ="hello,";
$hello .="how are you?";
echo "$hello"; // will print hello, how are you? 


But, without the period

PHP Code:

$hello ="hello,";
$hello ="how are you?";
echo "$hello"; // will print how are you?