<s>
du	B-Application
(	O
abbreviated	O
from	O
disk	B-Application
usage	I-Application
)	O
is	O
a	O
standard	O
Unix	B-Application
program	B-Application
used	O
to	O
estimate	O
file	O
space	O
usage	O
—	O
space	O
used	O
under	O
a	O
particular	O
directory	B-Application
or	O
files	B-Operating_System
on	O
a	O
file	B-Application
system	I-Application
.	O
</s>
<s>
A	O
Windows	B-Application
commandline	O
version	O
of	O
this	O
program	B-Application
is	O
part	O
of	O
Sysinternals	O
suite	O
by	O
Mark	O
Russinovich	O
.	O
</s>
<s>
The	O
du	B-Application
utility	O
first	O
appeared	O
in	O
version	O
1	O
of	O
AT&T	O
UNIX	B-Application
.	O
</s>
<s>
The	O
version	O
of	O
du	B-Application
bundled	O
in	O
GNU	B-Application
coreutils	I-Application
was	O
written	O
by	O
Torbjorn	O
Granlund	O
,	O
David	O
MacKenzie	O
,	O
Paul	O
Eggert	O
,	O
and	O
Jim	O
Meyering	O
.	O
</s>
<s>
The	O
command	B-Application
is	O
also	O
available	O
for	O
FreeDOS	B-Application
.	O
</s>
<s>
By	O
default	O
,	O
the	O
Single	O
UNIX	B-Application
Specification	O
(	O
SUS	O
)	O
specifies	O
that	O
du	B-Application
is	O
to	O
display	O
the	O
file	O
space	O
allocated	O
to	O
each	O
file	O
and	O
directory	B-Application
contained	O
in	O
the	O
current	O
directory	B-Application
.	O
</s>
<s>
Links	O
will	O
be	O
displayed	O
as	O
the	O
size	O
of	O
the	O
link	O
file	O
,	O
not	O
what	O
is	O
being	O
linked	O
to	O
;	O
the	O
size	O
of	O
the	O
content	O
of	O
directories	B-Application
is	O
displayed	O
,	O
as	O
expected	O
.	O
</s>
<s>
As	O
du	B-Application
reports	O
allocation	O
space	O
and	O
not	O
absolute	O
file	O
space	O
,	O
the	O
amount	O
of	O
space	O
on	O
a	O
file	B-Application
system	I-Application
shown	O
by	O
du	B-Application
may	O
vary	O
from	O
that	O
shown	O
by	O
df	B-Device
if	O
files	B-Operating_System
have	O
been	O
deleted	B-Application
but	O
their	O
blocks	O
not	O
yet	O
freed	O
.	O
</s>
<s>
Also	O
the	O
minfree	O
setting	O
that	O
allocates	O
datablocks	O
for	O
the	O
filesystem	B-Application
and	O
the	O
super	O
user	O
processes	O
creates	O
a	O
discrepancy	O
between	O
total	O
blocks	O
and	O
the	O
sum	O
of	O
used	O
and	O
available	O
blocks	O
.	O
</s>
<s>
The	O
minfree	O
setting	O
is	O
usually	O
set	O
to	O
about	O
5%	O
of	O
the	O
total	O
filesystem	B-Application
size	O
.	O
</s>
<s>
du	B-Application
takes	O
a	O
single	O
argument	O
,	O
specifying	O
a	O
pathname	O
for	O
to	O
work	O
;	O
if	O
it	O
is	O
not	O
specified	O
,	O
the	O
current	O
directory	B-Application
is	O
used	O
.	O
</s>
<s>
-d	O
0	O
sums	O
at	O
the	O
current	O
level	O
,	O
-d	O
1	O
sums	O
at	O
the	O
subdirectory	B-Application
,	O
-d	O
2	O
at	O
sub-subdirectories	O
,	O
etc	O
.	O
</s>
<s>
,	O
only	O
traverse	O
files	B-Operating_System
and	O
directories	B-Application
on	O
the	O
device	O
on	O
which	O
the	O
pathname	O
argument	O
is	O
specified	O
.	O
</s>
<s>
Other	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
may	O
add	O
extra	O
options	O
.	O
</s>
<s>
For	O
example	O
,	O
BSD	O
and	O
GNU	B-Operating_System
du	B-Application
specify	O
a	O
option	O
,	O
displaying	O
disk	B-Application
usage	I-Application
in	O
a	O
format	O
easier	O
to	O
read	O
by	O
the	O
user	O
,	O
adding	O
units	O
with	O
the	O
appropriate	O
SI	O
prefix	O
(	O
e.g.	O
</s>
<s>
Sum	O
of	O
directories	B-Application
(	O
-s	O
)	O
in	O
kilobytes	O
(	O
-k	O
)	O
:	O
</s>
<s>
Sum	O
of	O
directories	B-Application
(	O
-s	O
)	O
in	O
human-readable	B-General_Concept
format	I-General_Concept
(	O
-h	O
:	O
Byte	B-Application
,	O
Kilobyte	O
,	O
Megabyte	O
,	O
Gigabyte	O
,	O
Terabyte	O
and	O
Petabyte	O
)	O
:	O
</s>
<s>
disk	B-Application
usage	I-Application
of	O
all	O
subdirectories	B-Application
and	O
files	B-Operating_System
including	O
hidden	O
files	B-Operating_System
within	O
the	O
current	O
directory	B-Application
(	O
sorted	O
by	O
filesize	O
)	O
:	O
</s>
<s>
disk	B-Application
usage	I-Application
of	O
all	O
subdirectories	B-Application
and	O
files	B-Operating_System
including	O
hidden	O
files	B-Operating_System
within	O
the	O
current	O
directory	B-Application
(	O
sorted	O
by	O
reverse	O
filesize	O
)	O
:	O
</s>
<s>
The	O
weight	O
(	O
size	O
)	O
of	O
each	O
subdirectory	B-Application
under	O
the	O
current	O
directory	B-Application
(	O
-d	O
1	O
)	O
with	O
a	O
sum	O
total	O
at	O
the	O
end	O
(	O
-c	O
)	O
all	O
displayed	O
in	O
human-readable	B-General_Concept
format	I-General_Concept
(	O
-h	O
)	O
:	O
</s>
<s>
or	O
with	O
du	B-Application
from	O
GNU	B-Operating_System
:	O
</s>
<s>
The	O
weight	O
(	O
size	O
)	O
of	O
subdirectories	B-Application
under	O
the	O
root	O
directory	B-Application
(	O
-d	O
1	O
,	O
trailing	O
/	O
)	O
with	O
a	O
sum	O
total	O
at	O
the	O
end	O
(	O
-c	O
)	O
,	O
all	O
displayed	O
in	O
human-readable	B-General_Concept
format	I-General_Concept
(	O
-h	O
)	O
without	O
traversing	O
into	O
other	O
filesystems	B-Application
(	O
-x	O
)	O
.	O
</s>
<s>
Useful	O
when	O
/var	O
/tmp	O
or	O
other	O
directories	B-Application
are	O
on	O
separate	O
storage	O
from	O
the	O
root	O
directory	B-Application
:	O
</s>
<s>
or	O
with	O
du	B-Application
from	O
GNU	B-Operating_System
:	O
</s>
