my $dbh=DBI->connect('dbi:mysql:database=foo; host=localhost; mysql_socket=/var/run/mysqld/mysqld.sock', 'myuser', 'myuserpass');

##</code><code>##

$ENV{MYSQL_UNIX_PORT}='/var/run/mysqld/mysqld.sock';

my $dbh=DBI->connect('dbi:mysql:database=foo; host=localhost', 'myuser', 'myuserpass');