du doesn't add up?

Daravon · 01-09-2012, 02:40 PM

When I change to my website directory and run

Code:

du BKM/

I get the following output:

Code:

chaz@optimus:~/docs/tiWobs$ du BKM/
//a bunch of files and subdirectories
28352	BKM/
chaz@optimus:~/docs/tiWobs$

However when I paste this output into a spreadsheet, and add up all the sizes (leaving out the last line of course) I get some 54k and not 28k. Why the discrepancy? Which one is right?

tronayne · 01-09-2012, 04:17 PM

Try the "human" option to du:

Code:

du -hs dir

will only show a summary (in bytes, megabytes, gigabytes, etc.). Without an argument, du reports in blocks (see the manual page).

Hope this helps some.

wpeckham · 01-09-2012, 04:31 PM

Without the -s option, du will report the disk usage for every file AND FOLDER below the current level (default), or the parameters on the command line.

Since it reports the space a file takes, then also reports that space as part of the space taken by the folder HOLDING that file, the total of all those lines will ALWAYS add to more than the total space actually used. Adding the -s makes it report space used ONLY by the (s)ingle entities listed as parameters (or the current folder if you provide no parameters).

If the man page does not make it clear, there are online documents that describe these commands and options in finer detail. (Or, you can ask here.)

Daravon · 01-09-2012, 04:35 PM

Quote:

Since it reports the space a file takes, then also reports that space as part of the space taken by the folder HOLDING that file, the total of all those lines will ALWAYS add to more than the total space actually used.

Oh wow. Of course. I'm glad I asked this in the newbie forum...