def command_regression(self):
        import socket
        import string
        try:
            mail_subject = 'Boost regression for %s on %s' % ( self.tag,
                string.split(socket.gethostname(), '.')[0] )
            start_time = time.localtime()
            if self.mail:
                self.log( 'Sending start notification to "%s"' % self.mail )
                self.send_mail(
                    '%s started at %s.' % ( mail_subject, format_time( start_time ) )
                    )