Given lines of credit card numbers, mask the first 12 digits of each credit card number with an asterisk (i.e., *) and print the masked card number on a new line. Each credit card number consists of four space-separated groups of four digits. For example, the credit card number 1234 5678 9101 1234 would be masked and printed as **** **** **** 1234.
How can we do it with the sed command, I'm not getting how to deal with spaces?
Sample Input
1234 5678 9101 1234
2999 5178 9101 2234
Sample Output
**** **** **** 1234
**** **** **** 2234
$ echo -e "hello
1234 5678 9101 1234
2999 5178 9101 2234
something else" | sed -E "s/^[0-9]{4} [0-9]{4} [0-9]{4} ([0-9]{4})\b/**** **** **** \1/g"
hello
**** **** **** 1234
**** **** **** 2234
something else
If you want to preserve the possibility of spaces ...
$ echo -e "hello
1234567891011234
2999 5178 9101 2234
something else" | sed -E "s/^[0-9]{4}(\s*)[0-9]{4}(\s*)[0-9]{4}(\s*)([0-9]{4})\b/****\1****\2****\3\4/g"
hello
************1234
**** **** **** 2234
something else
If you always want intermediate spaces in the output (even if not in the input), then replace \1, \2, and \3 with literal spaces.