awk 字典的遍历

例如要过滤 nginx 的 access 日志，access 日志大概长这样：

89.248.165.21 - - [19/Nov/2022:22:25:44 +0800] "\x03\x00\x00\x13\x0E\xE0\x00\x00\x00\x00\x00\x01\x00\x08\x00\x02\x00\x00\x00" 400 157 "-" "-" "-"
141.255.166.2 - - [19/Nov/2022:22:27:16 +0800] "GET / HTTP/1.1" 502 157 "-" "Hello World" "-"

通过下面的 awk 命令来统计IP 出现的次数和最后的访问时间

head -n 30 access.log-20221108 | awk -F '[][ ]' '
{
    iptime[$1] = $5; 
    ipcnt[$1] = ipcnt[$1] + 1
}
END{
    for (k in iptime) {
        print iptime[k], "\t", ipcnt[k], "\t", k 
    }
}' | sort -n -k 2 -r
07/Nov/2022:17:58:14     3   167.94.138.120
07/Nov/2022:16:31:11     3   113.219.249.245
07/Nov/2022:18:44:45     2   8.219.119.144
07/Nov/2022:17:58:24     2   116.213.38.106
07/Nov/2022:17:39:50     2   185.122.204.30
07/Nov/2022:17:22:46     2   51.159.164.227
07/Nov/2022:16:31:01     2   211.95.50.8
07/Nov/2022:16:31:01     2   125.124.63.167
07/Nov/2022:16:31:00     2   101.227.1.199
07/Nov/2022:16:27:24     2   109.237.97.180
07/Nov/2022:17:44:29     1   60.217.75.70
07/Nov/2022:16:48:43     1   92.118.39.78
07/Nov/2022:16:45:26     1   43.246.208.2
07/Nov/2022:16:42:53     1   220.196.160.144
07/Nov/2022:16:34:35     1   183.103.226.212
07/Nov/2022:16:31:04     1   101.227.1.198
07/Nov/2022:16:30:49     1   94.102.61.10
07/Nov/2022:16:30:48     1   111.7.96.150

参考：https://unix.stackexchange.com/questions/183279/how-to-view-all-the-content-in-an-awk-array