linux根据端口号，或进程名获取进程pid

1. 列出谁在使用某个端口

   lsof -i :{port}

   lsof(list open files)是一个列出当前系统打开文件的工具。在linux环境下，任何事物都以文件的形式存在，通过文件不仅仅可以访问常规数据，还可以访问网络连接和硬件。
   

   [root@localhost webapps]# lsof -i:20880
   COMMAND  PID USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
   java    8624 root  297u  IPv6 14992707      0t0  TCP localhost.localdomain:20880 (LISTEN)
   java    8624 root  316u  IPv6 14990166      0t0  TCP localhost.localdomain:43330->localhost.localdomain:20880 (ESTABLISHED)
   java    8624 root  317u  IPv6 14990167      0t0  TCP localhost.localdomain:20880->localhost.localdomain:43330 (ESTABLISHED)
   java    8624 root  596u  IPv6 14990943      0t0  TCP localhost.localdomain:43386->localhost.localdomain:20880 (ESTABLISHED)
   java    8624 root  597u  IPv6 14990181      0t0  TCP localhost.localdomain:20880->localhost.localdomain:43386 (ESTABLISHED)
   java    8624 root  671u  IPv6 14991724      0t0  TCP localhost.localdomain:43392->localhost.localdomain:20880 (ESTABLISHED)
   java    8624 root  672u  IPv6 14990211      0t0  TCP localhost.localdomain:20880->localhost.localdomain:43392 (ESTABLISHED)

2. netstat命令，求出进程PID，可进行其他操作，比如杀进程
   

   netstat -anp|grep {port}|awk '{printf $7}'|cut -d/ -f1

   [root@localhost webapps]# netstat -anp|grep 8080
   tcp6       0      0 :::8080                 :::*                    LISTEN      10027/java          
   [root@localhost webapps]# netstat -anp|grep 8080 |awk '{printf $7}'|cut -d/ -f1
   10027

   netstat -tunlp|grep {port}

   [root@localhost webapps]# netstat -tunlp|grep 8080
   tcp6       0      0 :::8080                 :::*                    LISTEN      10027/java          

    netstat -nlp | grep :{port}| awk '{print $7}' | awk -F"/" '{ print $1 }

   [root@localhost ~]# netstat -nlp | grep :8080
   tcp6       0      0 :::8080                 :::*                    LISTEN      27103/java          
   [root@localhost ~]# netstat -nlp | grep :8080 | awk '{print $7}' 
   27103/java
   [root@localhost ~]# netstat -nlp | grep :8080 | awk '{print $7}' | awk -F"/" '{ print $1 }'
   27103
   [root@localhost ~]# kill -9 $(netstat -nlp | grep :8088 | awk '{print $7}' | awk -F"/" '{ print $1 }') 

3. 其他命令
   

   ps命令：  ps -ef | grep {programName}

   [root@localhost ~]# ps -ef | grep tomcat
   root     27103     1  1 11月21 ?      00:21:48 /usr/bin/java -Djava.util.logging.config.file=/usr/local/apache-tomcat-8.0.53/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Dspring.profiles.active=test -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dignore.endorsed.dirs= -classpath /usr/local/apache-tomcat-8.0.53/bin/bootstrap.jar:/usr/local/apache-tomcat-8.0.53/bin/tomcat-juli.jar -Dcatalina.base=/usr/local/apache-tomcat-8.0.53 -Dcatalina.home=/usr/local/apache-tomcat-8.0.53 -Djava.io.tmpdir=/usr/local/apache-tomcat-8.0.53/temp org.apache.catalina.startup.Bootstrap start
   root     29611 29302  0 17:40 pts/0    00:00:00 grep --color=auto tomcat

   pgrep命令（pgrep命令的p表明了这个命令是专门用于进程查询的grep）：

   pgrep {programName}   这个命令不知道为什么不管用，啧啧

4. shell 杀进程

   pid0=$(netstat -nlp | grep :20880 | awk '{print $7}' | awk -F"/" '{ print $1 }');
   # 杀掉对应的进程，如果pid不存在，则不执行
   if [ -n "$pid0" ]; then
   kill -s 9 $pid0;
   fi

   另一种根据端口号杀进程的方法，根据更好用

   ps -ef | grep tomcat | grep -v grep | awk '{print $2}' | xargs kill -9
   [root@localhost ~]# lsof -i:20881
   COMMAND   PID USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
   java    27103 root  513u  IPv6 15892971      0t0  TCP localhost.localdomain:20881 (LISTEN)
   java    27103 root  520u  IPv6 15895638      0t0  TCP localhost.localdomain:60750->localhost.localdomain:20881 (ESTABLISHED)
   java    27103 root  521u  IPv6 15891070      0t0  TCP localhost.localdomain:20881->localhost.localdomain:60750 (ESTABLISHED)
   java    27103 root  609u  IPv6 15895639      0t0  TCP localhost.localdomain:60778->localhost.localdomain:20881 (ESTABLISHED)
   java    27103 root  610u  IPv6 15891079      0t0  TCP localhost.localdomain:20881->localhost.localdomain:60778 (ESTABLISHED)
   java    27103 root  756u  IPv6 15891110      0t0  TCP localhost.localdomain:60808->localhost.localdomain:20881 (ESTABLISHED)
   java    27103 root  757u  IPv6 15893007      0t0  TCP localhost.localdomain:20881->localhost.localdomain:60808 (ESTABLISHED)
   [root@localhost ~]# netstat -anp|grep 20881|awk '{printf $7}'|cut -d/ -f1 | xargs kill -9
   [root@localhost ~]# lsof -i:20881
   [root@localhost ~]# netstat -anp|grep 20881|awk '{printf $7}'|cut -d/ -f1 | xargs kill -9
   kill: 找不到进程“---”

参考文章链接：

1.   lsof命令具体用法   https://www.cnblogs.com/sparkbj/p/7161669.html