Using wildcard metacharacters and options to the ls command, view the following: a. All the files that end with .cfg under the /etc directory b. All hidden files in the /home/user1 directory c. The directory names that exist under the /var directory d. All the files that start with the letter "a" underneath the /bin directory e. All the files that have exactly three letters in their filename in the /bin directory f. All files that have exactly three letters in their filename and end with either the letter "t" or the letter "hr" in the /bin directory