我們經常用到netstat命令查看主機連接狀況，包括連接ip、端口、狀態等，今天就練習下shell分析netsat結果。

描述

假設netstat命令運行的結果我們存儲在nowcoder.txt里，格式如下：

Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:6160 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 172.16.56.200:41856 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:49822 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:49674 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:42316 172.16.34.143:3306 ESTABLISHED
tcp 0 0 172.16.56.200:44076 172.16.240.74:6379 ESTABLISHED
tcp 0 0 172.16.56.200:49656 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:58248 100.100.142.4:80 TIME_WAIT
tcp 0 0 172.16.56.200:50108 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:41944 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:35548 100.100.32.118:80 TIME_WAIT
tcp 0 0 172.16.56.200:39024 100.100.45.106:443 TIME_WAIT
tcp 0 0 172.16.56.200:41788 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:58260 100.100.142.4:80 TIME_WAIT
tcp 0 0 172.16.56.200:41812 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:41854 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:58252 100.100.142.4:80 TIME_WAIT
tcp 0 0 172.16.56.200:49586 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:41754 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:50466 120.55.222.235:80 TIME_WAIT
tcp 0 0 172.16.56.200:38514 100.100.142.5:80 TIME_WAIT
tcp 0 0 172.16.56.200:49832 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:52162 100.100.30.25:80 ESTABLISHED
tcp 0 0 172.16.56.200:50372 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:50306 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:49600 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:41908 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:60292 100.100.142.1:80 TIME_WAIT
tcp 0 0 172.16.56.200:37650 100.100.54.133:80 TIME_WAIT
tcp 0 0 172.16.56.200:41938 172.16.34.144:3306 ESTABLISHED
tcp 0 0 172.16.56.200:49736 172.16.0.24:3306 ESTABLISHED
tcp 0 0 172.16.56.200:41890 172.16.34.144:3306 ESTABLISHED
udp 0 0 127.0.0.1:323 0.0.0.0:*
udp 0 0 0.0.0.0:45881 0.0.0.0:*
udp 0 0 127.0.0.53:53 0.0.0.0:*
udp 0 0 172.16.56.200:68 0.0.0.0:*
udp6 0 0 ::1:323 :::*
raw6 0 0 :::58 :::* 7

現在需要你查看和本機3306端口建立連接并且狀態是established的所有IP，按照連接數降序排序。你的腳本應該輸出

10 172.16.0.24

9 172.16.34.144

1 172.16.34.143

思路：先篩選出端口3306以及狀態established的行，然后取出其ip，再用awk對其進行統計，可以使用數組，也可以直接使用uniq -c，兩個腳本如下：

cat nowcoder.txt | grep ":3306" | 
awk '{if($6=="ESTABLISHED") print $5}' | 
awk -F: '{res[$1]++}END{for(i in res) print res[i]" "i}' | sort -rn

cat nowcoder.txt | grep ":3306" | grep "ESTABLISHED" |
awk '{print $5}' | awk -F: '{print $1}' | sort | uniq -c | sort -rn | awk '{print $1,$2}'

最后，請教個問題，這里兩個grep是否可以合并，該怎么寫？

grep ":3306" | grep "ESTABLISHED"

注意：3306和ESTABLISHED之間有多個空格，數量不定