“du [options] [directories]

Print disk usage (as the number of 1 KB blocks used by each named directory and its subdirectories; default is the current directory).
Options
-a, –all

Print disk usage for all files, not just subdirectories.

-b, –bytes

Print sizes in bytes.

-c, –total

In addition to normal output, print grand total of all arguments.

-D, –dereference-args

Follow symbolic links, but only if they are command-line arguments.

-h, –human-readable

Print sizes in human-readable format.

-H, –si

Like -h, but show as power of 1000 rather than 1024.

-k, –kilobytes

Print sizes in kilobytes (this is the default).

-l, –count-links

Count the size of all files, whether or not they have already appeared (i.e., via a hard link).”oreilly.com