Delete multiple lines above and below from a matching pattern in a file using awk/sed/grep

Question

I have file.txt containing:

registered 
{ 
    hostname-1 
    { 
        AAA 32; 
        BBB uuid-1;
        ip 192.168.1.1;
        host hostname-1;
        ...
        ...
        ...
    } 
} 
registered 
{
    hostname-2
    {
        AAA 31;
        BBB uuid-2;
        ip 192.168.1.2;
        host hostname-2;
        ...
        ...
        ...
    }
}
registered
{
    hostname-3
    {
        AAA 33;
        BBB uuid-3;
        ip 192.168.1.3;
        host hostname-3;
        ...
        ...
        ...
    }
}

I want to delete one complete registered block based on matching ip.

Eg if ip is 192.168.1.2 then the output should be:

registered
{
    hostname-1
    {
        AAA 32;
        BBB uuid-1;
        ip 192.168.1.1;
        host hostname-1;
        ...
        ...
        ...
    }
}
registered
{
    hostname-3
    {
        AAA 33;
        BBB uuid-3;
        ip 192.168.1.3;
        host hostname-3;
        ...
        ...
        ...
    } 
}

I tried 2 ways to achieve this but could not make it work

1) Using grep: this did not work.

grep -v -B6 -A6 $IP file.txt > out.txt
mv -f out.txt file.txt

2) Using awk: If I give the exact IP in the awk command below then it works

awk '/192.168.1.2/{for(x=NR-6;x<=NR+6;x++)d[x];}{a[NR]=$0}END{for(i=1;i<=NR;i++)if(!(i in d))print a[i]}' file.txt

But I want to pass the variable $IP in the awk command. It is not working

awk -v pattern="${IP}" '$0 ~ pattern/{for(x=NR-6;x<=NR+6;x++)d[x];}{a[NR]=$0}END{for(i=1;i<=NR;i++)if(!(i in d))print a[i]}' file.txt

Any help to find out the problem here would be greatly appreciated.

Thanks.

Answer 1

This might work for you (GNU sed):

sed -n '/^registered/h;//!H;/^}/!b;g;/192\.168\.1\.2/!p' file

Providing the file is as is. This will gather up entire registered blocks and delete the one(s) which contain the string 192.168.1.2 .

Answer 2

IP=192.168.1.2
awk '/'$IP'/{for(x=NR-6;x<=NR+6;x++)d[x];}{a[NR]=$0}END{for(i=1;i<=NR;i++)if(!(i in d))print a[i]}' file.txt