14.2 du: Estimate file space usage
du reports the amount of disk space used by the specified files
and for each subdirectory (of directory arguments). Synopsis:
du [option]... [file]...
With no arguments, du reports the disk space for the current
directory. Normally the disk space is printed in units of
1024 bytes, but this can be overridden (see Block size).
Non-integer quantities are rounded up to the next higher unit.
If two or more hard links point to the same file, only one of the hard
links is counted. The file argument order affects which links
are counted, and changing the argument order may change the numbers
that du outputs.
The program accepts the following options. Also see Common options.
- ‘-a’
- ‘--all’
- Show counts for all files, not just directories.
- ‘--apparent-size’
- Print apparent sizes, rather than disk usage. The apparent size of a
file is the number of bytes reported by
wc -c
on regular files,
or more generally, ls -l --block-size=1
or stat --format=%s
.
For example, a file containing the word ‘zoo’ with no newline would,
of course, have an apparent size of 3. Such a small file may require
anywhere from 0 to 16 KiB or more of disk space, depending on
the type and configuration of the file system on which the file resides.
However, a sparse file created with this command:
dd bs=1 seek=2GiB if=/dev/null of=big
has an apparent size of 2 GiB, yet on most modern
systems, it actually uses almost no disk space.
- ‘-b’
- ‘--bytes’
- Equivalent to
--apparent-size --block-size=1
.
- ‘-B size’
- ‘--block-size=size’
- Scale sizes by size before printing them (see Block size).
For example, -BG prints sizes in units of 1,073,741,824 bytes.
- ‘-c’
- ‘--total’
- Print a grand total of all arguments after all arguments have
been processed. This can be used to find out the total disk usage of
a given set of files or directories.
- ‘-D’
- ‘--dereference-args’
- Dereference symbolic links that are command line arguments.
Does not affect other symbolic links. This is helpful for finding
out the disk usage of directories, such as /usr/tmp, which
are often symbolic links.
- ‘--files0-from=file’
-
Disallow processing files named on the command line, and instead process
those named in file file; each name being terminated by a zero byte
(ASCII nul).
This is useful
when the list of file names is so long that it may exceed a command line
length limitation.
In such cases, running du via xargs is undesirable
because it splits the list into pieces and makes du print
with the --total (-c) option for each sublist rather than for the entire list.
One way to produce a list of ASCII nul terminated file
names is with gnu
find, using its -print0 predicate.
If file is ‘-’ then the ASCII nul terminated
file names are read from standard input.
- ‘-h’
- ‘--human-readable’
- Append a size letter to each size, such as ‘M’ for mebibytes.
Powers of 1024 are used, not 1000; ‘M’ stands for 1,048,576 bytes.
This option is equivalent to --block-size=human-readable.
Use the --si option if you prefer powers of 1000.
- ‘-H’
- Equivalent to --dereference-args (-D).
- ‘-k’
- Print sizes in 1024-byte blocks, overriding the default block size
(see Block size).
This option is equivalent to --block-size=1K.
- ‘-l’
- ‘--count-links’
- Count the size of all files, even if they have appeared already (as a
hard link).
- ‘-L’
- ‘--dereference’
- Dereference symbolic links (show the disk space used by the file
or directory that the link points to instead of the space used by
the link).
- ‘-m’
- Print sizes in 1,048,576-byte blocks, overriding the default block size
(see Block size).
This option is equivalent to --block-size=1M.
- ‘-P’
- ‘--no-dereference’
- For each symbolic links encountered by du,
consider the disk space used by the symbolic link.
- ‘-d depth’
- ‘--max-depth=depth’
- Show the total for each directory (and file if –all) that is at
most MAX_DEPTH levels down from the root of the hierarchy. The root
is at level 0, so
du --max-depth=0
is equivalent to du -s
.
- ‘-0’
- ‘--null’
- Output a zero byte (ASCII nul) at the end of each line,
rather than a newline. This option enables other programs to parse the
output of du even when that output would contain data
with embedded newlines.
- ‘--si’
- Append an SI-style abbreviation to each size, such as ‘M’ for
megabytes. Powers of 1000 are used, not 1024; ‘M’ stands for
1,000,000 bytes. This option is equivalent to
--block-size=si. Use the -h or
--human-readable option if
you prefer powers of 1024.
- ‘-s’
- ‘--summarize’
- Display only a total for each argument.
- ‘-S’
- ‘--separate-dirs’
- Normally, in the output of du (when not using --summarize),
the size listed next to a directory name, d, represents the sum
of sizes of all entries beneath d as well as the size of d itself.
With --separate-dirs, the size reported for a directory name,
d, is merely the
stat.st_size
-derived size of the directory
entry, d.
- ‘--time’
- Show time of the most recent modification of any file in the directory,
or any of its subdirectories.
- ‘--time=ctime’
- ‘--time=status’
- ‘--time=use’
- Show the most recent status change time (the ‘ctime’ in the inode) of
any file in the directory, instead of the modification time.
- ‘--time=atime’
- ‘--time=access’
- Show the most recent access time (the ‘atime’ in the inode) of
any file in the directory, instead of the modification time.
- ‘--time-style=style’
- List timestamps in style style. This option has an effect only if
the --time option is also specified. The style should
be one of the following:
- ‘+format’
- List timestamps using format, where format is interpreted
like the format argument of date (see date invocation).
For example, --time-style="+%Y-%m-%d %H:%M:%S" causes
du to list timestamps like ‘2002-03-30 23:45:56’. As
with date, format's interpretation is affected by the
LC_TIME locale category.
- ‘full-iso’
- List timestamps in full using ISO 8601 date, time, and time zone
format with nanosecond precision, e.g., ‘2002-03-30
23:45:56.477817180 -0700’. This style is equivalent to
‘+%Y-%m-%d %H:%M:%S.%N %z’.
- ‘long-iso’
- List ISO 8601 date and time in minutes, e.g.,
‘2002-03-30 23:45’. These timestamps are shorter than
‘full-iso’ timestamps, and are usually good enough for everyday
work. This style is equivalent to ‘+%Y-%m-%d %H:%M’.
- ‘iso’
- List ISO 8601 dates for timestamps, e.g., ‘2002-03-30’.
This style is equivalent to ‘+%Y-%m-%d’.
You can specify the default value of the --time-style option
with the environment variable TIME_STYLE; if TIME_STYLE is not set
the default style is ‘long-iso’. For compatibility with ls,
if TIME_STYLE begins with ‘+’ and contains a newline,
the newline and any later characters are ignored; if TIME_STYLE
begins with ‘posix-’ the ‘posix-’ is ignored; and if
TIME_STYLE is ‘locale’ it is ignored.
- ‘-x’
- ‘--one-file-system’
- Skip directories that are on different file systems from the one that
the argument being processed is on.
- ‘--exclude=pattern’
- When recursing, skip subdirectories or files matching pattern.
For example,
du --exclude='*.o'
excludes files whose names
end in ‘.o’.
- ‘-X file’
- ‘--exclude-from=file’
- Like --exclude, except take the patterns to exclude from file,
one per line. If file is ‘-’, take the patterns from standard
input.
On BSD systems, du reports sizes that are half the correct
values for files that are NFS-mounted from HP-UX systems. On HP-UX
systems, it reports sizes that are twice the correct values for
files that are NFS-mounted from BSD systems. This is due to a flaw
in HP-UX; it also affects the HP-UX du program.
An exit status of zero indicates success,
and a nonzero value indicates failure.