DUC(1) General Commands Manual DUC(1)

duc - index, query and graph disk usage

duc subcommand options

Duc is a collection of tools for inspecting and visualizing disk usage.

Duc maintains an indexed database of accumulated sizes of directories of your file system, and allows you to query this database with some tools, or create fancy sunburst graphs to show you where your bytes are.

Duc scales quite well, it has been tested on systems with more then 500 million files and several petabytes of storage.

Duc comes with a command line tool called duc, which is used to create, maintain and query the disk usage database. run duc help to get a list of available commands. duc help <subcommand> describes the usage of a specific subcommand. Run duc help --all for an extensive list of all commands and their options.

Some commands might not be available on your system, depending on the exact configuration chosen when building Duc. (For example, the duc gui command is not available in the duc-nox package on Debian and Ubuntu)

Duc allows any option to be placed either on the command line or in a configuration file. Options on the command line are preceded by a double-leading-dash (--option), some options have a corresponding short option which can be used as well with a single leading dash. (-o)

At startup duc tries to read its configuration from three locations in this particular order: /etc/ducrc, ~/.config/duc/ducrc, ~/.ducrc and ./.ducrc.

A configuration file consists of sections and parameters. The section names correspond to the duc subcommands for which the parameters in that section apply. A section begins with the name of the section in square brackets and continues until the next section begins. Sections contain parameters, one per line, which consist of a single option name for boolean flags, or an option name and a value for options which take a value. See the EXAMPLES section for an example of the configuration file format.

Duc needs an index file of the file system before it is able to show any information. To create the index, run the duc index command. For example, to create an index of your home directory run duc index ~

$ duc index /usr
Skipping lost+found: Permission denied
Indexed 333823 files and 48200 directories, (35.0GB total) in 1 seconds

The default location of the database is $HOME/.duc.db. To use a different database location, use the DUC_DATABASE environment variable or specify the database location with the --database argument.

You can run duc index at any time later to rebuild the index.

By default Duc indexes all directories it encounters during file system traversal, including special file systems like /proc and /sys, and network file systems like NFS or Samba mounts. There are a few options to select what parts of your filesystem you want to include or exclude from the scan, check the documentation below for the options --one-file-system, --exclude, --fs-exclude and --fs-include for more details.

Duc has various subcommands for querying or exploring the index: (Note that depending on your configuration, some of these commands might not be available)

○
duc info shows a list of available directory trees in the database, and the time and date of the last scan.
○
duc ls lists all files and directories under the given path on the console.
○
duc ui runs a ncurses based console user interface for exploring the file system usage.
○
duc gui starts a graphical (X11) interface representing the file system in a sunburst graph. Click on a directory to redraw the graph from the perspective of the selected directory. Click in the center of the graph to go up one directory in the tree.

This section list all available subcommands and describes their usage and options.

These options apply to all Duc subcommands:

increase verbosity to debug level
show help
quiet mode, do not print any warning
increase verbosity
output version information and exit

Options for command duc help [options]:

show complete help for all commands

The 'index' subcommand performs a recursive scan of the given paths on the filesystem and calculates the inclusive size of all directories. The results are written to the index, and can later be queried by one of the other duc tools.

Options for command duc index [options] PATH ...:

show file size in exact number of bytes
use database file VAL
exclude files matching VAL
count hard links only once. if two or more hard links point to the same file, only one of the hard links is displayed and counted
force writing in case of corrupted db
exclude file system type VAL during indexing. VAL is a comma separated list of file system types as found in your systems fstab, for example ext3,ext4,dosfs
include file system type VAL during indexing. VAL is a comma separated list of file system types as found in your systems fstab, for example ext3,ext4,dosfs
hide file names in index (privacy). the names of directories will be preserved, but the names of the individual files will be hidden
limit index to only files/dirs owned by uid
limit index to only files/dirs owned by username
limit directory names to given depth. when this option is given duc will traverse the complete file system, but will only the first VAL levels of directories in the database to reduce the size of the index
skip directories on different file systems
show progress during indexing
do not update database, just crawl
do not use compression for database. Duc enables compression if the underlying database supports this. This reduces index size at the cost of slightly longer indexing time

Options for command duc info [options]:

show apparent instead of actual file size
show file size in exact number of bytes
select database file to use [~/.duc.db]

The 'ls' subcommand queries the duc database and lists the inclusive size of all files and directories on the given path. If no path is given the current working directory is listed.

Options for command duc ls [options] [PATH]...:

show apparent instead of actual file size
use ASCII characters instead of UTF-8 to draw tree
show file size in exact number of bytes
append file type indicator (one of */) to entries
colorize output (only on ttys)
show number of files instead of file size
select database file to use [~/.duc.db]
list directory itself, not its contents
list only directories, skip individual files
show full path instead of tree in recursive view
draw graph with relative size for each entry
traverse up to ARG levels deep [4]
sort output by name instead of by size
recursively list subdirectories

Options for command duc xml [options] [PATH]:

interpret min_size/-s value as apparent size
select database file to use [~/.duc.db]
exclude file from xml output, only include directories
specify min size for files or directories

Options for command duc json [options] [PATH]:

interpret min_size/-s value as apparent size
select database file to use [~/.duc.db]
exclude file from json output, only include directories
specify min size for files or directories

The 'graph' subcommand queries the duc database and generates a sunburst graph showing the disk usage of the given path. If no path is given a graph is created for the current working directory.

By default the graph is written to the file 'duc.png', which can be overridden by using the -o/--output option. The output can be sent to stdout by using the special file name '-'.

Options for command duc graph [options] [PATH]:

Show apparent instead of actual file size
select database file to use [~/.duc.db]
show number of files instead of file size
set destination resolution in DPI [96.0]
select output format png|svg|pdf|html [png]
use radius fuzz factor when drawing graph [0.7]
draw graph with color gradient
draw up to ARG levels deep [4]
output file name [duc.png]
select palette. available palettes are: size, rainbow, greyscale, monochrome, classic
leave a gap of VAL pixels between rings
image size [800]

Options for command duc cgi [options] [PATH]:

Show apparent instead of actual file size
show file size in exact number of bytes
show number of files instead of file size
url of CSS style sheet to use instead of default CSS
select database file to use [~/.duc.db]
set destination resolution in DPI [96.0]
select HTML file to include as footer
use radius fuzz factor when drawing graph [0.7]
draw graph with color gradient
select HTML file to include as header
draw up to ARG levels deep [4]
generate table with file list
select palette. available palettes are: size, rainbow, greyscale, monochrome, classic
leave a gap of VAL pixels between rings
image size [800]
enable tooltip when hovering over the graph. enabling the tooltip will cause an asynchronous HTTP request every time the mouse is moved and can greatly increase the HTTP traffic to the web server

The 'gui' subcommand queries the duc database and runs an interactive graphical utility for exploring the disk usage of the given path. If no path is given the current working directory is explored.

The following keys can be used to navigate and alter the graph:

+           increase maximum graph depth
-           decrease maximum graph depth
0           Set default graph depth
a           Toggle between apparent and actual disk usage
b           Toggle between exact byte count and abbreviated sizes
c           Toggle between file size and file count
f           toggle graph fuzz
g           toggle graph gradient
p           toggle palettes
backspace   go up one directory

Options for command duc gui [options] [PATH]:

show apparent instead of actual file size
show file size in exact number of bytes
show number of files instead of file size
use dark background color
select database file to use [~/.duc.db]
use radius fuzz factor when drawing graph
draw graph with color gradient
draw up to VAL levels deep [4]
select palette. available palettes are: size, rainbow, greyscale, monochrome, classic
leave a gap of VAL pixels between rings

The 'ui' subcommand queries the duc database and runs an interactive ncurses utility for exploring the disk usage of the given path. If no path is given the current working directory is explored.

The following keys can be used to navigate and alter the file system:

up, pgup, j:     move cursor up
down, pgdn, k:   move cursor down
home, 0:         move cursor to top
end, $:          move cursor to bottom
left, backspace: go up to parent directory (..)
right, enter:    descent into selected directory
a:               toggle between actual and apparent disk usage
b:               toggle between exact and abbreviated sizes
c:               Toggle between file size and file count
h:               show help. press 'q' to return to the main screen
n:               toggle sort order between 'size' and 'name'
o:               try to open the file using xdg-open
q, escape:       quit

Options for command duc ui [options] [PATH]:

show apparent instead of actual file size
show file size in exact number of bytes
show number of files instead of file size
select database file to use [~/.duc.db]
sort output by name instead of by size
do not use colors on terminal output

The duc binary has support for a rudimentary CGI interface, currently only tested with apache. The CGI interface generates a simple HTML page with a list of indexed directories, and shows a clickable graph for navigating the file system. If the option --list is given, a list of top sized files/dirs is also written.

Configuration is done by creating a simple shell script as .cgi in a directory which is configured for CGI execution by your web server (usually /usr/lib/cgi-bin). The shell script should simply start duc, and pass the location of the database to navigate.

An example duc.cgi script would be

#!/bin/sh
/usr/local/bin/duc cgi -d /home/jenny/.duc.db
○
Make sure the database file is readable by the user (usually www-data)
○
Debugging is best done by inspecting the web server's error log
○
Make sure the .cgi script has execute permissions (chmod +x duc.cgi)

Some notes:

○
The HTML page is generated with a simple embedded CSS style sheet. If the style is not to your liking you can provide an external CSS url with the --css-url option which will then be used instead of the embedded style definition.
○
Add the option --list to generate a table of top sized files and directories in the HTML page.
○
The options --header and --footer allow you to insert your own HTML code before and after the main.

The current CGI configuration is not very flexible, nor secure. It is not advised to run the CGI from public reachable web servers, use at your own risk.

The concepts of 'file size' and 'disk usage' can be a bit confusing. Files on disk have an apparent size, which indicates how much bytes are in the file from the users point of view; this is the size reported by tools like ls -l. The apparent size can be any number, from 0 bytes up to several TB. The actual number of bytes which are used on the filesystem to store the file can differ from this apparent size for a number of reasons: disks store data in blocks, which cause files to always take up a multiple of the block size, files can have holes ('sparse' files), and other technical reasons. This number is always a multiple of 512, which means that the actual size used for a file is almost always a bit more then its apparent size.

Duc has two modes for counting file sizes:

○
apparent size: this is the size as reported by ls. This number indicates the file length, which is usually smaller then the actual disk usage.
○
actual size: this is the size as reported by du and df. The actual file size tells you how much disk is actually used by a file, and is always a multiple of 512 bytes.

The default mode used by duc is to use the 'actual size'. Most duc commands to report disk usage (duc ls, duc graph, duc ui, etc) have an option to change between these two modes (usually the -a), or use the 'a' key to toggle.

If you use git clone to pull down the latest release, you will have to do the following:

git clone https://github.com/zevv/duc
cd duc
autoreconf -i

Then you can run the regular

./configure [ options ]
make

to the regular build of the software.

A note for Redhat and derivates users. The package providing the development file for lmdb (lmdb-devel) does not include a lmdb.pc pkgconfig file. This could lead to errors during the configure phase:

checking for LMDB... no
configure: error: Package requirements (lmdb) were not met:

To avoid the need to call pkg-config, you may set the environment variables
LMDB_CFLAGS and LMDB_LIBS:

LMDB_CFLAGS=" " LMDB_LIBS=-llmdb ./configure --with-db-backend=lmdb [ options ]

Index the /usr directory, writing to the default database location ~/.duc.db:

$ duc index /usr

List all files and directories under /usr/local, showing relative file sizes in a graph:

$ duc ls -Fg /usr/local
  4.7G lib/                 [+++++++++++++++++++++++++++++++++++++++++++]
  3.1G share/               [++++++++++++++++++++++++++++               ]
  2.7G src/                 [++++++++++++++++++++++++                   ]
814.9M bin/                 [+++++++                                    ]
196.6M include/             [+                                          ]
 66.6M x86_64-w64-mingw32/  [                                           ]
 59.9M local/               [                                           ]
 38.8M i686-w64-mingw32/    [                                           ]
 20.3M sbin/                [                                           ]
 13.6M lib32/               [                                           ]
 13.3M libx32/              [                                           ]

or use the -R options for the tree view:

$ duc ls -RF /etc/logcheck
 24.0K `+- ignore.d.server/
  4.0K  |  `+- hddtemp
  4.0K  |   |- ntpdate
  4.0K  |   |- lirc
  4.0K  |   |- rsyslog
  4.0K  |   `- libsasl2-modules
  8.0K  |- ignore.d.workstation/
  4.0K  |   `- lirc
  8.0K  `- ignore.d.paranoid/
  4.0K      `- lirc

Start the graphical interface to explore the file system using sunburst graphs:

$ duc gui /usr

Generate a graph of /usr/local in .png format:

$ duc graph -o /tmp/usr.png /usr

The following sample configuration file defines default parameters for the duc ls and duc ui commands and defines a global option to configure the database path which is used by all subcommands

[global]
database /var/cache/duc.db
[ls]
recursive
classify
color
[ui]
no-color
apparent

○
What does the error 'Database version mismatch mean?'
The layout of the index database sometimes changes when new features are implemented. When you get this error you have probably upgraded to a newer version. Just remove the old database file and rebuild the index.
○
Duc crashes with a segmentation fault, is it that buggy?
By default Duc uses the Tokyocabinet database backend. Tokyocabinet is pretty fast, stores the database in a single file and has nice compression support to keep the database small. Unfortunately, it is not always robust and sometimes chokes on corrupt database files. Try to remove the database and rebuild the index. If the error persists contact the authors.
○
Some of the Duc subcommands like duc gui are not available on my system?
Depending on the configuration that was chosen when building Duc, some options might or might not be available in the duc utility. For example, on Debian or Ubuntu Duc comes in two flavours: there is a full featured package called duc, or a package without dependencies on X-windows called duc-nox, for which the latter lacks the duc gui command.
○
duc index is hogging my system and using a lot of CPU and I/O!
Traversing a file system is hard work - which is the exact reason why Duc exists in the first place. You can use the default tools to make Duc behave nice towards other processes on your machine, use something like:
nice 19 ionice -c 3 duc index [options]
This makes duc index run with the lowest CPU and I/O scheduler priorities, which is nicer to all the other processes on your machine.

At startup duc tries to read its configuration from three locations in this particular order: /etc/ducrc, ~/.config/duc/ducrc, ~/.ducrc and ./.ducrc.

Duc mainains an index of scanned directories, which defaults to ~/.duc.db. All tools take the -d/--database option to override the database path.

○
Ico Doornekamp duc@zevv.nl
○
John Stoffel john@stoffel.org

Other contributors can be found in the Git log at GitHub.

Duc is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 dated June, 1991. Duc is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

July 2022