14.2 du: Estimate file space usage

du reports the space needed to represent a set of files. Synopsis:

du [option]… [file]…

With no arguments, du reports the space needed to represent the files at or under the current directory. Normally the 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 and entries that du outputs.

The program accepts the following options. Also see Common options.

-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 even when that output would contain data with embedded newlines.

-a
--all

Show counts for all files, not just directories.

--apparent-size

Print apparent sizes, rather than file system 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 file system 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 file systems, it actually uses almost no space.

Apparent sizes are meaningful only for regular files and symbolic links. Other file types do not contribute to apparent size.

-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.

-b
--bytes

Equivalent to --apparent-size --block-size=1.

-c
--total

Print a grand total of all arguments after all arguments have been processed. This can be used to find out the total file system 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 file system usage of directories, such as /usr/tmp, which are often symbolic links.

-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.

--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

Equivalent to --dereference-args (-D).

-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.

--inodes

List inode usage information instead of block usage. This option is useful for finding directories which contain many files, and therefore eat up most of the inodes space of a file system (see df, option --inodes). It can well be combined with the options -a, -c, -h, -l, -s, -S, -t and -x; however, passing other options regarding the block size, for example -b, -m and --apparent-size, is ignored.

-k

Print sizes in 1024-byte blocks, overriding the default block size (see Block size). This option is equivalent to --block-size=1K.

-L
--dereference

Dereference symbolic links (show the file system space used by the file or directory that the link points to instead of the space used by the link).

-l
--count-links

Count the size of all files, even if they have appeared already (as a hard 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 link encountered by du, consider the file system space used by the symbolic link itself.

-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, will exclude the size of any subdirectories.

--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.

-t size
--threshold=size

Exclude entries based on a given size. The size refers to used blocks in normal mode (see Block size), or inodes count in conjunction with the --inodes option.

If size is positive, then du will only print entries with a size greater than or equal to that.

If size is negative, then du will only print entries with a size smaller than or equal to that.

Although GNU find can be used to find files of a certain size, du’s --threshold option can be used to also filter directories based on a given size.

When combined with the --apparent-size option, the --threshold option elides entries based on apparent size. When combined with the --inodes option, it elides entries based on inode counts.

Here’s how you would use --threshold to find directories with a size greater than or equal to 200 megabytes:

du --threshold=200MB

Here’s how you would use --threshold to find directories and files – the -a – with an apparent size smaller than or equal to 500 bytes:

du -a -t -500 --apparent-size

Here’s how you would use --threshold to find directories on the root file system with more than 20000 inodes used in the directory tree below:

du --inodes -x --threshold=20000 /
--time

Show the most recent modification timestamp (mtime) of any file in the directory, or any of its subdirectories. See File timestamps.

--time=ctime
--time=status
--time=use

Show the most recent status change timestamp (ctime) of any file in the directory, or any of its subdirectories. See File timestamps.

--time=atime
--time=access

Show the most recent access timestamp (atime) of any file in the directory, or any of its subdirectories. See File timestamps.

--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: Print or set system date and time). For example, --time-style="+%Y-%m-%d %H:%M:%S" causes du to list timestamps like ‘2020-07-21 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-like date, time, and time zone components with nanosecond precision, e.g., ‘2020-07-21 23:45:56.477817180 -0400’. This style is equivalent to ‘+%Y-%m-%d %H:%M:%S.%N %z’.

long-iso

List ISO 8601 date and time components with minute precision, e.g., ‘2020-07-21 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., ‘2020-07-21’. 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 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.

--exclude=pattern

When recursing, skip subdirectories or files matching pattern. For example, du --exclude='*.o' excludes files whose names end in ‘.o’.

-x
--one-file-system

Skip directories that are on different file systems from the one that the argument being processed is on.

Since du relies on information reported by the operating system, its output might not reflect the space consumed in the underlying devices. For example;

For these reasons du might better be thought of as an estimate of the size of a tar or other conventional backup for a set of files, rather than as a measure of space consumed in the underlying devices.

An exit status of zero indicates success, and a nonzero value indicates failure.