Question 3: a Try listing all the files/folders under /usr/bin. It should show a long list of programs in that folder. In that list, you can see the program file date, the program file echo, and Is. Please do screenshots to prove that you find those programs. Question 4: Suppose we have a folder, folder1 under /home/ec2-user. folder1 has another folder, folder2. Why does the following command fail? [ec2-user@ip-172-31-48-178 folder1] $ rm folder1 rm: cannot remove 'folderl': No such file or directory