##PHP 139 128 bytes

 $u=-1;$i=$argv[1];while($u<=strlen($i)){$c+=($u*(substr($i,-(abs($u)),1)));$u +=$u<0?3:1;}echo($c>0&&!($c%11)&&$u>8&&$u<11?1:0);

Could not get the CLI to just echo the true of false. Had to make do it this way. Any ideas?

128 bytes: Turned "true" and "false" to 1 and 0.

PHP 139 128 bytes

 $u=-1;$i=$argv[1];while($u<=strlen($i)){$c+=($u*(substr($i,-(abs($u)),1)));$u +=$u<0?3:1;}echo($c>0&&!($c%11)&&$u>8&&$u<11?1:0);

Could not get the CLI to just echo the true of false. Had to make do it this way. Any ideas?

128 bytes: Turned "true" and "false" to 1 and 0.

##PHP 139 bytes

 $u=-1;$i=$argv[1];while($u<=strlen($i)){$c+=($u*(substr($i,-(abs($u)),1)));$u +=$u<0?3:1;}echo($c>0&&!($c%11)&&$u>8&&$u<11?"true":"false");

Could not get the CLI to just echo the true of false. Had to make do it this way. Any ideas?

##PHP 139 128 bytes

 $u=-1;$i=$argv[1];while($u<=strlen($i)){$c+=($u*(substr($i,-(abs($u)),1)));$u +=$u<0?3:1;}echo($c>0&&!($c%11)&&$u>8&&$u<11?1:0);

Could not get the CLI to just echo the true of false. Had to make do it this way. Any ideas?

128 bytes: Turned "true" and "false" to 1 and 0.