NCDU(1) ncdu manual NCDU(1)
NAME
ncdu - NCurses Disk Usage
SYNOPSIS
ncdu [options] dir
DESCRIPTION
ncdu (NCurses Disk Usage) is a curses-based version of the well-known
'du', and provides a fast way to see what directories are using your
disk space.
OPTIONS
Mode Selection
-h, --help
Print a short help message and quit.
-v, -V, --version
Print ncdu version and quit.
-f FILE
Load the given file, which has earlier been created with the "-o"
option. If FILE is equivalent to "-", the file is read from
standard input.
For the sake of preventing a screw-up, the current version of ncdu
will assume that the directory information in the imported file
does not represent the filesystem on which the file is being
imported. That is, the refresh, file deletion and shell spawning
options in the browser will be disabled.
dir Scan the given directory.
-o FILE
Export all necessary information to FILE instead of opening the
browser interface. If FILE is "-", the data is written to standard
output. See the examples section below for some handy use cases.
Be warned that the exported data may grow quite large when
exporting a directory with many files. 10.000 files will get you an
export in the order of 600 to 700 KiB uncompressed, or a little
over 100 KiB when compressed with gzip. This scales linearly, so be
prepared to handle a few tens of megabytes when dealing with
millions of files.
-e, --extended, --no-extended
Enable/disable extended information mode. This will, in addition to
the usual file information, also read the ownership, permissions
and last modification time for each file. This will result in
higher memory usage (by roughly ~30%) and in a larger output file
when exporting.
When using the file export/import function, this flag will need to
be added both when exporting (to make sure the information is added
to the export), and when importing (to read this extra information
in memory). This flag has no effect when importing a file that has
been exported without the extended information.
This enables viewing and sorting by the latest child mtime, or
modified time, using 'm' and 'M', respectively.
--ignore-config
Do not attempt to load any configuration files.
Scan Options
These options affect the scanning progress, and have no effect when
importing directory information from a file.
-x, --one-file-system
Do not cross filesystem boundaries, i.e. only count files and
directories on the same filesystem as the directory being scanned.
--cross-file-system
Do cross filesystem boundaries. This is the default, but can be
specified to overrule a previously given "-x".
--exclude PATTERN
Exclude files that match PATTERN. The files will still be displayed
by default, but are not counted towards the disk usage statistics.
This argument can be added multiple times to add more patterns.
-X FILE, --exclude-from FILE
Exclude files that match any pattern in FILE. Patterns should be
separated by a newline.
--include-caches, --exclude-caches
Include (default) or exclude directories containing CACHEDIR.TAG.
The directories will still be displayed, but their contents will
not be scanned or counted towards the disk usage statistics.
<http://www.brynosaurus.com/cachedir/>
-L, --follow-symlinks, --no-follow-symlinks
Follow (or not) symlinks and count the size of the file they point
to. As of ncdu 1.14, this option will not follow symlinks to
directories and will count each symlinked file as a unique file
(i.e. unlike how hard links are handled). This is subject to
change in later versions.
--exclude-firmlinks, --follow-firmlinks
(MacOS only) Exclude or follow firmlinks.
--include-kernfs, --exclude-kernfs
(Linux only) Include (default) or exclude Linux pseudo filesystems,
e.g. /proc (procfs), /sys (sysfs).
The complete list of currently known pseudo filesystems is: binfmt,
bpf, cgroup, cgroup2, debug, devpts, proc, pstore, security,
selinux, sys, trace.
Interface options
-0 Don't give any feedback while scanning a directory or importing a
file, other than when a fatal error occurs. Ncurses will not be
initialized until the scan is complete. When exporting the data
with "-o", ncurses will not be initialized at all. This option is
the default when exporting to standard output.
-1 Similar to "-0", but does give feedback on the scanning progress
with a single line of output. This option is the default when
exporting to a file.
In some cases, the ncurses browser interface which you'll see after
the scan/import is complete may look garbled when using this
option. If you're not exporting to a file, "-2" is probably a
better choice.
-2 Provide a full-screen ncurses interface while scanning a directory
or importing a file. This is the only interface that provides
feedback on any non-fatal errors while scanning.
-q, --slow-ui-updates, --fast-ui-updates
Change the UI update interval while scanning or importing. Ncdu
will update the screen 10 times a second by default
("--fast-ui-updates"), this can be decreased to once every 2
seconds with "-q" or "--slow-ui-updates". This feature can be used
to save bandwidth over remote connections. This option has no
effect when "-0" is used.
--enable-shell, --disable-shell
Enable or disable shell spawning from the browser. This feature is
enabled by default when scanning a live directory and disabled when
importing from file.
--enable-delete, --disable-delete
Enable or disable the built-in file deletion feature. This feature
is enabled by default when scanning a live directory and disabled
when importing from file. Explicitly disabling the deletion feature
can work as a safeguard to prevent accidental data loss.
--enable-refresh, --disable-refresh
Enable or disable directory refreshing from the browser. This
feature is enabled by default when scanning a live directory and
disabled when importing from file.
-r Read-only mode. When given once, this is an alias for
"--disable-delete", when given twice it will also add
"--disable-shell", thus ensuring that there is no way to modify the
file system from within ncdu.
--si, --no-si
List sizes using base 10 prefixes, that is, powers of 1000 (KB, MB,
etc), as defined in the International System of Units (SI), instead
of the usual base 2 prefixes, that is, powers of 1024 (KiB, MiB,
etc).
--disk-usage, --apparent-size
Select whether to display disk usage (default) or apparent sizes.
Can also be toggled in the browser with the 'a' key.
--show-hidden, --hide-hidden
Show (default) or hide "hidden" and excluded files. Can also be
toggled in the browser with the 'e' key.
--show-itemcount, --hide-itemcount
Show or hide (default) the item counts column. Can also be toggled
in the browser with the 'c' key.
--show-mtime, --hide-mtime
Show or hide (default) the last modification time column. Can also
be toggled in the browser with the 'm' key. This option is ignored
when not in extended mode (see "-e").
--show-graph, --hide-graph
Show (default) or hide the relative size bar column. Can also be
toggled in the browser with the 'g' key.
--show-percent, --hide-percent
Show (default) or hide the relative size percent column. Can also
be toggled in the browser with the 'g' key.
--sort COLUMN
Change the default column to sort on. Accepted values are disk-
usage (the default), name, apparent-size, itemcount or mtime. The
latter only makes sense in extended mode, see "-e".
The column can be suffixed with -asc or -desc to set the order to
ascending or descending, respectively. e.g. "--sort=name-desc" will
sort by name in descending order.
--group-directories-first, --no-group-directories-first
Sort (or not) directories before files.
--confirm-quit, --no-confirm-quit
Require a confirmation before quitting ncdu. Very helpful when you
accidentally press 'q' during or after a very long scan.
--confirm-delete, --no-confirm-delete
Require a confirmation before deleting a file or directory. Enabled
by default, but can be disabled if you're absolutely sure you won't
accidentally press 'd'.
--color SCHEME
Select a color scheme. The following schemes are recognized: off to
disable colors, dark for a color scheme intended for dark
backgrounds and dark-bg for a variation of the dark color scheme
that also works in terminals with a light background.
The default is dark-bg unless the "NO_COLOR" environment variable
is set.
CONFIGURATION
Ncdu can be configured by placing command-line options in
"/etc/ncdu.conf" or "$HOME/.config/ncdu/config". If both files exist,
the system configuration will be loaded before the user configuration,
allowing users to override options set in the system configuration.
Options given on the command line will override options set in the
configuration files. The files will not be read at all when
"--ignore-config" is given on the command line.
The configuration file format is simply one command line option per
line. Lines starting with "#" are ignored. Example configuration file:
# Always enable extended mode
-e
# Disable file deletion
--disable-delete
# Exclude .git directories
--exclude .git
KEYS
? Show help + keys + about screen
up, down, j, k
Cycle through the items
right, enter, l
Open selected directory
left, <, h
Go to parent directory
n Order by filename (press again for descending order)
s Order by filesize (press again for descending order)
C Order by number of items (press again for descending order)
a Toggle between showing disk usage and showing apparent size.
M Order by latest child mtime, or modified time. (press again for
descending order) Requires the -e flag.
d Delete the selected file or directory. An error message will be
shown when the contents of the directory do not match or do not
exist anymore on the filesystem.
t Toggle dirs before files when sorting.
g Toggle between showing percentage, graph, both, or none. Percentage
is relative to the size of the current directory, graph is relative
to the largest item in the current directory.
c Toggle display of child item counts.
m Toggle display of latest child mtime, or modified time. Requires
the -e flag.
e Show/hide 'hidden' or 'excluded' files and directories. Please note
that even though you can't see the hidden files and directories,
they are still there and they are still included in the directory
sizes. If you suspect that the totals shown at the bottom of the
screen are not correct, make sure you haven't enabled this option.
i Show information about the current selected item.
r Refresh/recalculate the current directory.
b Spawn shell in current directory.
Ncdu will determine your preferred shell from the "NCDU_SHELL" or
"SHELL" variable (in that order), or will call "/bin/sh" if neither
are set. This allows you to also configure another command to be
run when he 'b' key is pressed. For example, to spawn the vifm(1)
file manager instead of a shell, run ncdu as follows:
export NCDU_SHELL=vifm
ncdu
Ncdu will set the "NCDU_LEVEL" environment variable or increment it
before spawning the shell. This variable allows you to detect when
your shell is running from within ncdu, which can be useful to
avoid nesting multiple instances of ncdu. Ncdu itself does not
(currently) warn when attempting to run nested instances.
q Quit
FILE FLAGS
Entries in the browser interface may be prefixed by a one-character
flag. These flags have the following meaning:
! An error occurred while reading this directory.
. An error occurred while reading a subdirectory, so the indicated
size may not be correct.
< File or directory is excluded from the statistics by using exclude
patterns.
> Directory is on another filesystem.
^ Directory is excluded from the statistics due to being a Linux
pseudo filesystem.
@ This is neither a file nor a folder (symlink, socket, ...).
H Same file was already counted (hard link).
e Empty directory.
EXAMPLES
To scan and browse the directory you're currently in, all you need is a
simple:
ncdu
If you want to scan a full filesystem, your root filesystem, for
example, then you'll want to use "-x":
ncdu -x /
Since scanning a large directory may take a while, you can scan a
directory and export the results for later viewing:
ncdu -1xo- / | gzip >export.gz
# ...some time later:
zcat export.gz | ncdu -f-
To export from a cron job, make sure to replace "-1" with "-0" to
suppress any unnecessary output.
You can also export a directory and browse it once scanning is done:
ncdu -o- | tee export.file | ./ncdu -f-
The same is possible with gzip compression, but is a bit kludgey:
ncdu -o- | gzip | tee export.gz | gunzip | ./ncdu -f-
To scan a system remotely, but browse through the files locally:
ssh -C user@system ncdu -o- / | ./ncdu -f-
The "-C" option to ssh enables compression, which will be very useful
over slow links. Remote scanning and local viewing has two major
advantages when compared to running ncdu directly on the remote system:
You can browse through the scanned directory on the local system
without any network latency, and ncdu does not keep the entire
directory structure in memory when exporting, so you won't consume much
memory on the remote system.
HARD LINKS
Every disk usage analysis utility has its own way of (not) counting
hard links. There does not seem to be any universally agreed method of
handling hard links, and it is even inconsistent among different
versions of ncdu. This section explains what each version of ncdu does.
ncdu 1.5 and below does not support any hard link detection at all:
each link is considered a separate inode and its size is counted for
every link. This means that the displayed directory sizes are incorrect
when analyzing directories which contain hard links.
ncdu 1.6 has basic hard link detection: When a link to a previously
encountered inode is detected, the link is considered to have a file
size of zero bytes. Its size is not counted again, and the link is
indicated in the browser interface with a 'H' mark. The displayed
directory sizes are only correct when all links to an inode reside
within that directory. When this is not the case, the sizes may or may
not be correct, depending on which links were considered as "duplicate"
and which as "original". The indicated size of the topmost directory
(that is, the one specified on the command line upon starting ncdu) is
always correct.
ncdu 1.7 and later has improved hard link detection. Each file that has
more than two links has the "H" mark visible in the browser interface.
Each hard link is counted exactly once for every directory it appears
in. The indicated size of each directory is therefore, correctly, the
sum of the sizes of all unique inodes that can be found in that
directory. Note, however, that this may not always be same as the space
that will be reclaimed after deleting the directory, as some inodes may
still be accessible from hard links outside it.
BUGS
Directory hard links are not supported. They will not be detected as
being hard links, and will thus be scanned and counted multiple times.
Some minor glitches may appear when displaying filenames that contain
multibyte or multicolumn characters.
All sizes are internally represented as a signed 64bit integer. If you
have a directory larger than 8 EiB minus one byte, ncdu will clip its
size to 8 EiB minus one byte. When deleting items in a directory with a
clipped size, the resulting sizes will be incorrect.
Item counts are stored in a signed 32-bit integer without overflow
detection. If you have a directory with more than 2 billion files,
quite literally anything can happen.
On macOS 10.15 and later, running ncdu on the root directory without
`--exclude-firmlinks` may cause directories to be scanned and counted
multiple times. Firmlink cycles are currently (1.16) not detected, so
it may also cause ncdu to get stuck in an infinite loop and eventually
run out of memory.
Please report any other bugs you may find at the bug tracker, which can
be found on the web site at https://dev.yorhel.nl/ncdu
AUTHOR
Written by Yoran Heling <projects@yorhel.nl>.
SEE ALSO
du(1)
ncdu-1.18 2022-11-30 NCDU(1)
Generated by dwww version 1.15 on Tue Jun 25 08:03:24 CEST 2024.