This is first line.a This is over_second line. This is over_fourth line. This is third line. This is over_fourth delete it. This is over_fourth and one more. This is over_second with another text.
Need to delete lines where partial match occur, i.e if over_second occurs in another line, then whole line should get deleted. So output will be as follows;
This is first line. This is over_second line. This is third line. This is over_fourth line.
I could only come up with:
over_\w+ for selecting section of text. But don't know how to recognize duplicates, and delete whole line.