This system is linux mint 18.3, basically ubuntu.
sudo du --apparent-size -sb /tmp yields 476mb on my system currently.
if I run
sudo du --apparent-size -sb /tmp/* /tmp/.??* and add it all up, I get about 4mb.
(I know -b includes --apparent-size, just want to be explicit for this question)
Actually, to find the sum since I'm lazy, so I ran:
sudo du --apparent-size -sb /tmp/* /tmp/.??* | cut -f 1 | paste -sd+ - | bc
Why the difference? Are there some hidden files in /tmp that du isn't finding, or is there a mistake in my commands?
edit: despite my poor
.??* to catch .dirs and .files, there were no .a, .b, .c etc files in this case.