www crond(pam_unix)[

大家好，我的服务/var/log/message上面出现大量这样的信息，请问知道大概是什么意思啊？

Jul 19 11:02:01 www crond(pam_unix)[5323]: session closed for user root
Jul 19 11:03:01 www crond(pam_unix)[5362]: session opened for user root by (uid=0)
Jul 19 11:03:01 www crond(pam_unix)[5362]: session closed for user root
Jul 19 11:04:01 www crond(pam_unix)[5396]: session opened for user root by (uid=0)
Jul 19 11:04:01 www crond(pam_unix)[5396]: session closed for user root
Jul 19 11:05:01 www crond(pam_unix)[5434]: session opened for user root by (uid=0)
Jul 19 11:05:01 www crond(pam_unix)[5434]: session closed for user root
Jul 19 11:06:01 www crond(pam_unix)[5460]: session opened for user root by (uid=0)
Jul 19 11:06:01 www crond(pam_unix)[5460]: session closed for user root
Jul 19 11:07:01 www crond(pam_unix)[5474]: session opened for user root by (uid=0)
Jul 19 11:07:01 www crond(pam_unix)[5474]: session closed for user root
Jul 19 11:08:01 www crond(pam_unix)[5500]: session opened for user root by (uid=0)
Jul 19 11:08:01 www crond(pam_unix)[5500]: session closed for user root
Jul 19 11:09:01 www crond(pam_unix)[5510]: session opened for user root by (uid=0)
Jul 19 11:09:01 www crond(pam_unix)[5510]: session closed for user root
Jul 19 11:10:01 www crond(pam_unix)[5531]: session opened for user root by (uid=0)
Jul 19 11:10:01 www crond(pam_unix)[5531]: session closed for user root
Jul 19 11:11:01 www crond(pam_unix)[5550]: session opened for user root by (uid=0)
Jul 19 11:11:01 www crond(pam_unix)[5550]: session closed for user root
Jul 19 11:12:01 www crond(pam_unix)[5590]: session opened for user root by (uid=0)
Jul 19 11:12:01 www crond(pam_unix)[5590]: session closed for user root
Jul 19 11:13:01 www crond(pam_unix)[5605]: session opened for user root by (uid=0)
Jul 19 11:13:01 www crond(pam_unix)[5605]: session closed for user root
Jul 19 11:14:01 www crond(pam_unix)[5640]: session opened for user root by (uid=0)
Jul 19 11:14:01 www crond(pam_unix)[5640]: session closed for user root
Jul 19 11:15:01 www crond(pam_unix)[5686]: session opened for user root by (uid=0)
Jul 19 11:15:01 www crond(pam_unix)[5686]: session closed for user root
Jul 19 11:16:01 www crond(pam_unix)[5723]: session opened for user root by (uid=0)
Jul 19 11:16:01 www crond(pam_unix)[5723]: session closed for user root
Jul 19 11:17:01 www crond(pam_unix)[5741]: session opened for user root by (uid=0)
Jul 19 11:17:02 www crond(pam_unix)[5741]: session closed for user root
Jul 19 11:18:01 www crond(pam_unix)[5768]: session opened for user root by (uid=0)
Jul 19 11:18:01 www crond(pam_unix)[5768]: session closed for user root

知道什么问题，谢谢，原来是我写了一个脚本 没分钟执行一次。