:!perl /tmp/t.pl
--8<--
DBI:mysql:
    database=pl_test:
    host=localhost:
    port=3306
--8<--
do failed: No database selected
--8<--
DBI:mysql: database=pl_test: host=localhost: port=3306
--8<--
do failed: No database selected
--8<--
DBI:mysql:database=pl_test:host=localhost:port=3306
--8<--
do executed.