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Finding a match and deleting the line above to it..

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# 1  
Old 12-13-2012
Computer Finding a match and deleting the line above to it..
Hi All,
I have a file with the data:
Code:
Sun is Hot
Moon is cool
;
 
-- Mon Sep 10 08:54:10 CDT 2012
-- Mon Sep 11 08:54:10 CDT 2012
-- Mon Sep 12 08:54:10 CDT 2012
revoke connect from SREE;
delete from = 'SREE';
grant connect to SREE with 'fastcar8';

I want to remove the line above the line "revoke connect from SREE;" if the above line starts with only "--" otherwise don't delete. This should continue till all the lines above the revoke line, those start with "--" got deleted. If any space or any other character comes it should stop deleting.

Finally my output should look like:
Code:
Sun is Hot
Moon is cool
;
 
revoke connect from SREE;
delete from = 'SREE';
grant connect to SREE with 'fastcar8';

Please help me with this.

Thanks!!

Sreenivas
Last edited by raosr020; 12-13-2012 at 02:37 AM.. Reason: Minor changes
# 2  
Old 12-13-2012
Try

Code:
$awk '{if($0 ~ /^--/){A[++a]=$0}else if(a && $0 !~ /revoke connect from SREE/){for(i=1;i<=a;i++){print A[a]};a=0}else{print ;a=0}}' file
Sun is Hot
Moon is cool
;

revoke connect from SREE;
delete from = 'SREE';
grant connect to SREE with 'fastcar8';

# 3  
Old 12-13-2012
Code:
awk 'END{if(p)printf "%s",p} /^--/{p=p $0 RS; next} /revoke connect from SREE/{p=x} p{$0=p $0; p=x}1' infile

This User Gave Thanks to Scrutinizer For This Post:
raosr020
# 4  
Old 12-13-2012
Hi Pamu,

Thanks for the reply!!

But with that code any other revoke connect lines also getting deleted (ex: revoke connect from CALU is also getting deleted).

My original file:

Code:
Sun is Hot
Moon is cool
;

-- Mon Sep 10 08:54:10 CDT 2012
-- Mon Sep 11 08:54:10 CDT 2012
-- Mon Sep 12 08:54:10 CDT 2012
revoke connect from SREE;
delete from = 'SREE';
grant connect to SREE with 'fastcar8';
 
-- Mon Sep 12 08:54:10 CDT 2011
revoke connect from CALU;
delete from = 'CALU';
grant connect to CALU with 'calendar';

After running the below command:
Code:
awk '{if($0 ~ /^--/){A[++a]=$0}else if(a && $0 !~ /revoke connect from SREE/){for(i=1;i<=a;i++){print A[a]};a=0}else{print ;a=0}}' file

Output is as follows:
Code:
Sun is Hot
Moon is cool
;

revoke connect from SREE;
delete from = 'SREE';
grant connect to SREE with 'fastcar8';
 
-- Mon Sep 12 08:54:10 CDT 2011
delete from = 'CALU';
grant connect to CALU with 'calendar';

In above ouput
Code:
revoke connect from CALU;

line is missing. That shouldn't happen. Please correct the code.


And i cann't redirect this output to a temporary file. These changes should happen to the original file itself.

Please help me in getting these two requirements solved.

Thanks,
Sreenivas

---------- Post updated at 09:21 PM ---------- Previous update was at 06:50 PM ----------

Hi Scrutinizer

Thanks for the reply!!

Your code is not working. Please suggest me the solution based on the above requirement.

Thanks,
Sreenivas
Last edited by raosr020; 12-13-2012 at 11:46 AM.. Reason: changes made
# 5  
Old 12-13-2012
What isn't working? I get:

Code:
Sun is Hot
Moon is cool
;

revoke connect from SREE;
delete from = 'SREE';
grant connect to SREE with 'fastcar8';
 
-- Mon Sep 12 08:54:10 CDT 2011
revoke connect from CALU;
delete from = 'CALU';
grant connect to CALU with 'calendar';

What is your OS and version?
This User Gave Thanks to Scrutinizer For This Post:
raosr020
# 6  
Old 12-14-2012
Hi
Scrutinizer Image Image

Awesome!! Thanks alot!!
Your code is working perfect. Previously i used it wrongly. Now i have corrected my mistake. Its working fine.

But i have a concern about how to make the changes in the original file without redirecting stdout to some temporary new file.

Regards,
Sreenivas
# 7  
Old 12-14-2012
Hi, you are welcome. What is wrong with redirecting to a new file? You can rename it to the old file afterwards when satisfied with the result. It is the safest way..
This User Gave Thanks to Scrutinizer For This Post:
raosr020
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