Parse and delete lines efficiently

Shell Programming and Scripting
1

Hi

I have a set of options in the form of key value in a file. Need to find a particular value of 'a' and delete all lines till the next 'a' keyword .

Ex :

a bbb
c ddd
e fff
g hhh

a sss
c ggg
e xxx
f sss

a ddd
d sss
r sss
g hhh

and so forth

Here 'a' keyword is present in each stanza. I need to parse to find a particular value of 'a' (let's say 'sss') and from there, delete all lines till the next 'a' keyword.

Thanks

2

Always, give the input and the expected output and the condition.
It will be easier if you give the ouput.

3

Input

a bbb
c ddd
e fff
g hhh

a sss
c ggg
e xxx
f sss

a ddd
d sss
r sss
g hhh

Output

a bbb
c ddd
e fff
g hhh

a ddd
d sss
r sss
g hhh

4

Try this

awk  'NR%2==1{print}' RS="\n\n" ORS="\n\n" filename
5

Ranjith - Can you please explain your command below...

Let's assume I found the line with "a sss" using grep... all I now need to do is start deleting lines till I find the next keyword "a ..." (... can be any value)

Hope that gives better picture.

It's kind of
(while nextkeyword != 'a')
{
delete all lines inbetween
}

6

Hi,

Sorry misunderstood your requirement. Below script will delete the data from line starting with "a sss" untill the line starting with "a".

awk '$0~"^a" {flag=1} $0~"^a sss" {flag=0} flag==1'  filename

Regards,

Ranjith