my $dbh = DBI->connect("DBH:mysql:dbname=router:host=localhost","username","passwd", {'RaiseError' => 1 });

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Can't connect(DBH:mysql:dbname=router:host=localhost username passwd HASH(0x827b5ac)), no database driver specified and DBI_DSN env var not set at /var/www/localhost/cgi-bin/first.pl line 10