监控端口：
[root@super63 ~]# lsof -i :80
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
httpd 9308 root 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9310 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9311 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9312 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9313 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9314 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9315 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9316 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9317 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
httpd 9318 apache 4u IPv6 46922 0t0 TCP *:http (LISTEN)
删除后却依然占用空间的文件：
[root@super63 ~]# lsof | grep -i delete
mysqld 13976 mysql 4u REG 8,2 0 131138 /tmp/ibf596lR (deleted)
mysqld 13976 mysql 5u REG 8,2 0 131139 /tmp/ib6u85ea (deleted)
mysqld 13976 mysql 6u REG 8,2 0 131140 /tmp/ibfgq57s (deleted)
mysqld 13976 mysql 7u REG 8,2 0 131141 /tmp/ibYP8l1L (deleted)
mysqld 13976 mysql 11u REG 8,2 0 131142 /tmp/ibnlVpX4 (deleted)
