Linux AWK 命令用法简介

参考：
AWK简明教程
坐马桶拉大便的时读完却花了一上午。。。于是便秘了

准备工作

将netstat的输出重定向到文本文件

netstat -antl > netstat.txt

awk示例

1.使用awk提取netstat中的信息

awk '{print $1,$4}' netstat.txt

#将显示第1行和第4行的内容
tcp 127.0.0.1:5939
tcp 127.0.1.1:53
tcp 0.0.0.0:22
tcp 127.0.0.1:631
tcp 127.0.0.1:5432
tcp 0.0.0.0:8090
tcp 0.0.0.0:7
tcp 127.0.0.1:44329
tcp 127.0.0.1:3306
tcp 127.0.0.1:6379
tcp 0.0.0.0:13
tcp6 :::8080
tcp6 :::22
tcp6 ::1:631
tcp6 :::8088
tcp6 ::1:5432
tcp6 127.0.0.1:8005
tcp6 ::1:53615

2.使用awk进行格式化输出

awk '{printf "%-8s %-8s %-8s %-18s %-22s %-15s\n",$1,$2,$3,$4,$5,$6}' netstat.txt


tcp      0        0        127.0.0.1:5939     0.0.0.0:*              LISTEN         
tcp      0        0        127.0.1.1:53       0.0.0.0:*              LISTEN         
tcp      0        0        0.0.0.0:22         0.0.0.0:*              LISTEN         
tcp      0        0        127.0.0.1:631      0.0.0.0:*              LISTEN         
tcp      0        0        127.0.0.1:5432     0.0.0.0:*              LISTEN         
tcp      0        0        0.0.0.0:8090       0.0.0.0:*              LISTEN         
tcp      0        0        0.0.0.0:7          0.0.0.0:*              LISTEN         
tcp      0        0        127.0.0.1:44329    0.0.0.0:*              LISTEN         
tcp      0        0        127.0.0.1:3306     0.0.0.0:*              LISTEN         
tcp      0        0        127.0.0.1:6379     0.0.0.0:*              LISTEN         
tcp      0        0        0.0.0.0:13         0.0.0.0:*              LISTEN         
tcp      0        1        10.170.18.11:42514 117.34.37.32:443       LAST_ACK       
tcp      0        0        10.170.18.11:49747 192.30.253.125:443     ESTABLISHED    
tcp      1        0        127.0.0.1:51968    127.0.0.1:44329        CLOSE_WAIT     
tcp      0        1        10.170.18.11:42512 117.34.37.32:443       LAST_ACK       
tcp      0        1        10.170.18.11:35324 117.34.37.33:443       LAST_ACK       
tcp6     0        0        :::8080            :::*                   LISTEN         
tcp6     0        0        :::22              :::*                   LISTEN         
tcp6     0        0        ::1:631            :::*                   LISTEN         
tcp6     0        0        :::8088            :::*                   LISTEN         
tcp6     0        0        ::1:5432           :::*                   LISTEN         
tcp6     0        0        127.0.0.1:8005     :::*                   LISTEN         
tcp6     1        0        ::1:53615          ::1:631                CLOSE_WAIT     

3.使用awk过滤记录

比如说，只显示ESTABLISHED的连接

netstat -atnl | awk '$6=="ESTABLISHED" {printf "%8s %8s %8s %18s %20s %20s\n",$1,$2,$3,$4,$5,$6}'
tcp        0        0     127.0.0.1:5939            0.0.0.0:*          ESTABLISHED
tcp        0        0       127.0.1.1:53            0.0.0.0:*          ESTABLISHED
tcp        0        0         0.0.0.0:22            0.0.0.0:*          ESTABLISHED
tcp        0        0      127.0.0.1:631            0.0.0.0:*          ESTABLISHED
tcp        0        0     127.0.0.1:5432            0.0.0.0:*          ESTABLISHED
tcp        0        0       0.0.0.0:8090            0.0.0.0:*          ESTABLISHED
tcp        0        0    127.0.0.1:40770            0.0.0.0:*          ESTABLISHED
tcp        0        0          0.0.0.0:7            0.0.0.0:*          ESTABLISHED
tcp        0        0     127.0.0.1:3306            0.0.0.0:*          ESTABLISHED
tcp        0        0     127.0.0.1:6379            0.0.0.0:*          ESTABLISHED
tcp        0        0         0.0.0.0:13            0.0.0.0:*          ESTABLISHED
tcp6        0        0            :::8080                 :::*          ESTABLISHED
tcp6        0        0              :::22                 :::*          ESTABLISHED
tcp6        0        0            ::1:631                 :::*          ESTABLISHED
tcp6        0        0            :::8088                 :::*          ESTABLISHED
tcp6        0        0           ::1:5432                 :::*          ESTABLISHED
tcp6        0        0     127.0.0.1:8005                 :::*          ESTABLISHED

4.awk内建变量

比如输出行号：

awk '$6="ESTABLISHED" {print NR " " FNR " "  $0}' netstat.txt

比如指定分隔符：

awk 'BEGIN{FS=":"} {print $1,$3,$6}' /etc/passwd

awk -F: '{print $1,$3,$6}' OFS="\t" /etc/passwd

5.awk字符串匹配

可以利用正则表达式匹配

awk '$6 ~ /FIN|WAIT/ {print NR,$4,$5,$6}' OFS="\t" netstat.txt

也可以像grep一样匹配

awk '/ESTABLISHED/' netstat.txt

模式取反

awk  '$6 !~ /ESTABLISHED/' netstat.txt
#或者
awk '!/ESTABLISHED/ netstat.txt'

6.awk处理文件

awk拆分文件，使用重定向就好

awk 'NR!=1&&NR!=2 {print > $6}' netstat.txt
awk 'NR!=1&&NR!=2 {print $4,$5 > $6}' netstat.txt ## 指定列输出到文件

将按照第6列分隔文件

awk 'NR!=1&&NR!=2 {if($6 ~/TIME|ESTABLISHED/) print > "1.txt";else print >"2.txt"}' netstat.txt

指定输出文件

7.awk统计

计算所有.h .c .cpp文件大小总和，ls -l命令的文件大小将出现在第5列

ls -l *.cpp *.c *.h | awk '{sum+=$5} END {print sum}'

统计文件中某些字符出现的次数,
本例中将统计，各个状态的连接的个数

awk 'NR!=1&&NR!=2 {a[$6]++;} END {for (i in a )print i ", " a[i];}' netstat.txt 

统计每个用户的进程占了多少内存

ps aux | awk 'NR!=1{a[$1]+=$6;} END {for(i in a) print i ", " a[i]"KB"}'

8.几个例子

#从file中找出长度大于80的行
awk 'length>80' file

#连接数查看客户端IP
netstat -ntu4 | awk 'NR!=1&&NR!=2 {print $5}' | cut -d: -f1 | sort | uniq -c | sort -nr