I think your using du
in a Time Machine backup folder.
Per du
man page:
Directories having multiple hard links (typically Time Machine backups) are counted a single time per du execution.
So I think the aaa
, bbb
and ccc
files are hard links, and since they were counted in the result of the .
, they won't be counted again in the result for aaa
, bbb
or ccc
. That's also why the output of du -sk * .
doesn't show 677876, but only 4; the total of all the specified files/folders can't go over 677876.
Ref: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/du.1.html