'Sed' Command #5.sh

#Given an input file, with N credit card numbers, each in a new line, your task is to reverse the ordering of segments in each credit card number. Assume that the credit card numbers will have 4 space separated segments with 4 digits each.

#If the original credit card number is 1434 5678 9101 1234, transform it to 1234 9101 5678 1434.

sed -E 's/([0-9]{4}) ([0-9]{4}) ([0-9]{4}) ([0-9]{4})/\4 \3 \2 \1 /g'