'Grep'-B.sh

# Problem Link :- https://www.hackerrank.com/challenges/text-processing-in-linux-the-grep-command-5/problem
# Given an input file, with N credit card numbers, each in a new line, your task is to grep out 
# and output only those credit card numbers which have two or more consecutive occurences of the 
# same digit (which may be separated by a space, if they are in different segments). Assume that 
# the credit card numbers will have 4 space separated segments with 4 digits each.

grep '\([0-9]\) *\1'