-a     In  addition to the default output, report the size of each file not of type directory in the file
       hierarchy rooted in the specified file.  Regardless  of  the  presence  of  the  -a  option,  non-
       directories given as file operands shall always be listed.

-H     If  a  symbolic link is specified on the command line, du shall count the size of the file or file
       hierarchy referenced by the link.

-k     Write the files sizes in units of 1024 bytes, rather than the default 512-byte units.

-L     If a symbolic link is specified on the command line or encountered during the traversal of a  file
       hierarchy, du shall count the size of the file or file hierarchy referenced by the link.

-s     Instead of the default output, report only the total sum for each of the specified files.

-x     When  evaluating  file  sizes,  evaluate  only  those  files that have the same device as the file
       specified by the file operand.