1. netstat -anp |grep 端口號(hào)
   如下，我以3306為例，netstat -anp |grep 3306（此處備注下，如果我是以普通用戶操作，則需要加上sudo，如果是以root用戶操作，不用加sudo即可查看）

root@hadoop-master lib# netstat  -anp  |grep  3306
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      2953/mysqld     
tcp        0      0 127.0.0.1:32994         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 10.27.92.164:3306       10.26.94.145:36248      ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33242         ESTABLISHED 2953/mysqld     
tcp        0      0 10.27.92.164:3306       10.26.94.145:36246      ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33002         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33003         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:33012         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:3306          127.0.0.1:32998         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:33010         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33238         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33242         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33240         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33000         127.0.0.1:3306          ESTABLISHED 9591/java       

主要看監(jiān)控狀態(tài)為LISTEN表示已經(jīng)被占用，最后一列顯示被服務(wù)mysqld占用，查看具體端口號(hào)，只要有如圖這一行就表示被占用了

2. netstat -nultp
   該命令是查看當(dāng)前所有已經(jīng)使用的端口情況

root@hadoop-master lib# netstat -nultp  |grep  3306
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      2953/mysqld 

3. netstat -anp |grep 端口號(hào)

root@hadoop-master lib# netstat  -anp  |grep 3306
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      2953/mysqld     
tcp        0      0 127.0.0.1:32994         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 10.27.92.164:3306       10.26.94.145:36248      ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33242         ESTABLISHED 2953/mysqld     
tcp        0      0 10.27.92.164:3306       10.26.94.145:36246      ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33002         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33003         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:33012         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:3306          127.0.0.1:32998         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:33010         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33238         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33242         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33240         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33000         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 10.27.92.164:3306       10.26.94.145:36254      ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:3306          127.0.0.1:33010         ESTABLISHED 2953/mysqld     
tcp        0      0 127.0.0.1:32998         127.0.0.1:3306          ESTABLISHED 9591/java       
tcp        0      0 127.0.0.1:33003         127.0.0.1:3306          ESTABLISHED 9591/java       

殺死進(jìn)程：kill -9 pid