Instead of printing out the contents early on (which wouldn't allow it to work
with '-n'), I skip the loop that applies colors based on the regular expressions.
I added a 'line number' flag ('-n') which will print the line number
with padding before every line. To ensure that a line number isn't printed when
trying to 'ccat' an empty file, I added a check to see if the file is empty.
If it is, the program exits.
