Finding Last occurance of another pattern when a pattern is found.

Shell Programming and Scripting
1

Hi,

I have two files viz,

rak1:
$ cat rak1

rak2:

$ cat rak2

sdiff rak1 rak2

returns:

I want the lines that got modified, changed, or deleted preceding with the section they are in.

I have done this so far:

but I dont know how to put section in front of the changed,added or deleted lines.

Also it would be appreciated if the output could be printed as

[section X] <valInFile1/valInFile2> <valInFile1/valInFile2>
and so on.

Please Help me out

2

I do not see why you need the egrep. Use sed for that filtering - easy.
Now, using -n option you prevent sed from printing unnessesary line.
After that just print what you need: lines with section number and lines with changes:

> sdiff rak1 rak2 | grep -n "." | sed -n '/>$/d; /section/p; /[|<>]/p'

Ok, deleting still needed

The only not-nice, the sections with no changes will be in that printout

I could not get it by 'sed'
Easy with nawk:

>....|
nawk '{if ( ($0 !~ /section/) || (prev !~ /section/) ) print prev; prev=$0;}
        END{if ($0 !~ /section/) print $0;}'

Not clear why it has empty line in beginning and end; so, remove it by :

>...|nawk NF;