You pass parameters separated by commas to an identifier.
$first.seen(value1,value2)
and value1 is passed as $1, and value2 as $2. You can pass text or $identifiers or %variables. Note that if you're using a local variable, you must pass it to the alias as a parameter, since the alias can only see previously existing global variables.
As for your read problem you just now mentioned, it seems like your problem has changed. At first you were saying the read had failed, now it just isn't recognizing dupes as dupes. This will be harder for someone besides yourself to debug. However, by consolidating everything into a single alias, you avoid the need for the $first.seen() alias since the command only appears once in the new section. Also, a single consolidated section is easier to debug, rather than fixing a bug and needing to repeat the fix half a dozen times.
