Shell Programming and Scripting

what is the relationship between ABCD and BABA in the file, could you provide a data sample (not 1G, just an example of the desired string and the second desired string and how it is discovered?).

I repeat: Is this a homework assignment? Homework assignments need to be posted in the Homework & Coursework Forum and require that a questionnaire be filled out as specified in the rules for that forum.

When you grep for a string in a file, we generally expect to find that string (not a different string); but, obviously, grep will give you an entire line, not just the string you matched. If you show us the format of the file you are processing and show us a real-life example with a sample input file (shown in CODE tags), a string that you want to search for in that sample input file, explain what variables should be set as a result of searching that sample file, and show us what secondary search you want to perform based on those results; we might be able to understand what you're trying to do and suggest a way to approach the problem.

As I see you dont know what I mean.

Log file consist of bunch of information about transactions.
Each transaction has session_id and by this session_id I can identify some important things.

But first of all I need to look up for instance information about login, so I use :

Code:

grep loginWithIdCode file_log.txt

I get record something like this:

Code:

0F3CE08D6E53C97CD9B54A862B493D57 DEBUG (JSONConverter): JSON Request: {"idCode":*****,"reqType":"loginWithIdCode"}

And string 0F3CE08D6E53C97CD9B54A862B493D57 means session_id and by this session_id I would like to get all records from log file.

It is much more clear ?

A clear, precise, and detailed specification "ab initio" including some meaningful and representative samples could have avoided a long discussion, as we can see again.

If the line with your search pattern is the first line to be found in the file, try

Code:

awk '/loginWithIdCode/ {PAT=$1} $0 ~ PAT' file

When I look up session_id I would like to get all records again from log file which consist session_id.

Is there something you need done that the code suggested by RudiC didn't do?