Question

I have a log of following format

<<
[ABC] some other data
some other data
>>

<<
DEF some other data
some other data
>>

<<
[ABC] some other data
some other data
>>

I wanted to select all logs which are having ABC expected result is

<<
[ABC] some other data
some other data
>>

<<
[ABC] some other data
some other data
>>

What will the expression for sed command ?
For fetching contents b/w << >> expression will be

sed -e '/<</,/>>/!d' 

But how can I force it to have [ABC] in b/w

Answer 1

This works on my side:

awk '$0~/ABC/{print "<<";print;getline;print;getline;print }' temp.txt

tested as below:

pearl.242> cat temp.txt
<< 
[ABC] some other data 
some other data 
>>  
<< 
DEF some other data 
some other data 
>>  

nkeem

<< 
[ABC] some other data 
some other data 
>> 
pearl.243> awk '$0~/ABC/{print "<<";print;getline;print;getline;print }' temp.txt
<<
[ABC] some other data 
some other data 
>>  
<<
[ABC] some other data 
some other data 
>> 
pearl.244> 

If you donot want to hard code this statement print "<<";,then you can go for the below:

pearl.249> awk '$0~/ABC/{print x;print;getline;print;getline;print}{x=$0}' temp.txt
<< 
[ABC] some other data 
some other data 
>>  
<< 
[ABC] some other data 
some other data 
>> 
pearl.250>