sed删除指定行以及前n行

有文本文件，内容如下，需要找出response不为on的设备ip

root@dev[15:49:33]$ cat result.txt 
index[8] ip[8.8.8.8] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100     2  100     2    0     0   1031      0 --:--:-- --:--:-- --:--:--  2000
on]
index[4] ip[8.8.8.9] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100     2  100     2    0     0    883      0 --:--:-- --:--:-- --:--:--  2000
on]
index[5] ip[1.1.1.1] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    26  100    26    0     0  22127      0 --:--:-- --:--:-- --:--:-- 26000
local cache is unavailable]
index[3] ip[2.2.2.2] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100     2  100     2    0     0   1162      0 --:--:-- --:--:-- --:--:--  2000
on]
index[6] ip[3.3.3.3] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    26  100    26    0     0  22127      0 --:--:-- --:--:-- --:--:-- 26000
local cache is not found]
root@dev[15:51:36]$ 

删除指定行以及下面几行

root@dev[15:53:42]$ sed '/unavailable/,+7 d' result.txt 
index[8] ip[8.8.8.8] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100     2  100     2    0     0   1031      0 --:--:-- --:--:-- --:--:--  2000
on]
index[4] ip[8.8.8.9] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100     2  100     2    0     0    883      0 --:--:-- --:--:-- --:--:--  2000
on]
index[5] ip[1.1.1.1] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    26  100    26    0     0  22127      0 --:--:-- --:--:-- --:--:-- 26000
local cache is not found]
root@dev[15:53:53]$

删除指定行以及上面几行

root@dev[15:53:53]$ tac result.txt |sed '/^on]/,+3 d' |tac
index[5] ip[1.1.1.1] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    26  100    26    0     0  22127      0 --:--:-- --:--:-- --:--:-- 26000
local cache is unavailable]
index[6] ip[3.3.3.3] send response[  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    26  100    26    0     0  22127      0 --:--:-- --:--:-- --:--:-- 26000
local cache is not found]
root@dev[15:54:59]$