监听启动或是停止时提示如下错误：
TNS-12542: TNS:address already in use
TNS-12560: TNS:protocol adapter error
TNS-00512: Address already in use
Linux Error: 98: Address already in use
Listener failed to start. See the error message(s) above...
[oracle@rusky admin]$ netstat -anp | grep 1521 --查看哪些程序正在占用该端口
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 192.168.1.123:1521 0.0.0.0:* LISTEN 30763/tnslsnr
tcp 0 0 192.168.1.123:19295 192.168.1.123:1521 ESTABLISHED 30961/ora_pmon_bms2
tcp 0 0 192.168.1.123:1521 192.168.1.123:19295 ESTABLISHED 30763/tnslsnr
[oracle@rusky admin]$ kill -9 30763 --kill掉相应的程序
kill -9 30961
kill -9 30763
之后，重新启动监听正常。