I am new to awk.

Bhargav, how do you get those numbers stored in variable x?
Because I am on track something similar to this, where I am interested in numbers in a line present at even location.

And this array x need to be populated with unique values.

Also, please feel free to suggest me good links to start with learning awk & sed. So far to my observation they are powerful in terms of their usage in shell script.