UNIX gives us a way to do this by using a file name that starts with a period such as .secret. The -a means all files, even those beginning with a period.
Filenames can contain other special characters, including dashes, numbers, asterisks and blanks.
Generally these file names present problems for the shell unless the name is enclosed in double quotes. UNIX provides some shortcuts to enable you to do this. The asterisk character is used to match file names. The asterisk is one of several wildcard characters in UNIX, so named because they are like jokers in card games, which can be used for any card you need. Then it selects from this list those names that end in .c, and finally it sends this list to the wc command.