Question 2 (code not tested):

sub checkemail {
  my $email = shift;
  open IN, "/some/textfile.txt" or die "errormessage";
  while (<IN>) {
    chomp;
    return "already added" if $email eq $_;
    # if textfile.txt has one email address per line
    # and nothing else
  }
  close IN;
  return;
}
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Update (thanks to Hofmator for showing the obvious): dropped that error

This can be improved, but it should work. Hope it helps.

alex pleiner <alex@zeitform.de>
zeitform Internet Dienste