[SOLVED] Help sed delete before and after

tuxtutorials · 01-04-2011, 04:10 PM

Hello members,

I am stuck on a sed issue I can't seem to resolve. I am trying to get rid of lines before and after a regex match from the following dataset:

Code:

define host {
        host_name                       4000-somehost-app
        alias                           4000-somehost-app
        address                         192.168.2.30
        use                             4000-Host
}
define host {
        host_name                       4000-somehost2-app
        alias                           4000-somehost2-app
        address                         192.168.2.40
        use                             4000-Host
}

I have gotten this far but am stuck on how to proceed with removing additional lines in the beginning and a couple of lines forward:

Here is my attempt:

Code:

#!/bin/sh


sed -n '
        /define host/,/}/ {
                /4000-somehost-app/ D

                p
        }
'

My goal is to wipe out the "4000-somehost-app" and leave only "4000-somehost2-app". Can this be done with sed?

Any pointers on what I am doing wrong can be of great help.

Thanks

crts · 01-04-2011, 05:50 PM

Hi,

since your code already keeps only two lines I am assuming that you actually want to keep the entire block which contains '4000-somehost2-app'. This will delete anything else:

Code:

sed -nr '/define host/ {:a N; /}/ ! ba; /4000-somehost2-app/ p}' file

This will delete only the block that contains '4000-somehost-app'

Code:

sed -r '/define host/ {:a N; /}/ ! ba; /4000-somehost-app/ d}' file

Not sure what exactly you want.

tuxtutorials · 01-04-2011, 06:40 PM

Thanks crts,

Your line:

Code:

sed -r '/define host/ {:a N; /}/ ! ba; /4000-somehost-app/ d}' file

did it, I am going to go over this tomorrow and post back some questions regarding your approach.

Thanks again