my @password_table = read_password_table();

sub get_password($$) {
   my ($userid, $database) = @_;
   my @matches = grep m/^$userid:.+:$database:/,
                 @password_table;
   if ( @matches == 0 ) {
      warn  "found no entries for $userid/$database";
      return;
   } elsif ( @matches > 1 ) {
      warn "found multiple matches for $userid/$database";
      return;
   }

   if ( $matches[0] =~  m/^$userid:(.+):$database:/ ) {
      return $1;
   }

   confess "some sort of logic error must have occurred";
}
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