Grep Threading (7 Marks)

(Note: There was an error in the 2nd testcase, the error was rectified and a rejudge of all the submissions was performed. We are very sorry for the inconvenience.) Implement grep command using thread. You will be given an ls -lrt output as input. On a given string or name output the result. Given string can be substring of owner name, group name and file name. String will be case insensitive.