It’s amazing how many times I’ve need to find out the total size of all the files in a directory on one of our servers.
I have grown to love the simplicity of the `du` command.
du = Display disk Usage statistics
s tells us to display an entry for each specified file, while
h is for “human-readable” output.
This will use the unit suffixes of Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte.