ncdu - Man Page

-h, --help

Print a short help message and quit.

-v, -V, --version

Print version and quit.

-f file

Load the given file, which has earlier been created with the -o or -O flag. If file is equivalent to '-', the file is read from standard input. Reading from standard input is only supported for the JSON format.

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 the directory tree in JSON format 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.

Consider enabling -c to output Zstandard-compressed JSON, which can significantly reduce size of the exported data.

When running a multi-threaded scan or when scanning a directory tree that may not fit in memory, consider using -O instead.

-O file

Export the directory tree in binary format to file instead of opening the browser interface. If file is '-', the data is written to standard output. The binary format has built-in compression, supports low-memory multi-threaded export (in combination with -t) and can be browsed without importing the entire directory tree into memory.

-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 should 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.

These options affect the scanning progress, they 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 configured -x.

--exclude pattern

Exclude files that match pattern. The files are still displayed by default, but are not counted towards the disk usage statistics. This argument can be added multiple times to add more patterns.

-X, --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. Excluded cache directories are still displayed, but their contents will not be scanned or counted towards the disk usage statistics. https://bford.info/cachedir/

-L, --follow-symlinks, --no-follow-symlinks

Follow (or not) symlinks and count the size of the file they point to. This option does not follow symlinks to directories and will cause each symlinked file to count as a unique file. This is different from how hard links are handled. The exact counting behavior of this flag is subject to change in the future.

--include-kernfs, --exclude-kernfs

(Linux only) Include (default) or exclude Linux pseudo filesystems such as /proc (procfs) and /sys (sysfs).

The complete list of currently known pseudo filesystems is: binfmt, bpf, cgroup, cgroup2, debug, devpts, proc, pstore, security, selinux, sys, trace.

-t, --threads num

Number of threads to use when scanning the filesystem, defaults to 1.

In single-threaded mode, the JSON export (see -o) can operate with very little memory, but in multi-threaded mode the entire directory tree is first constructed in memory and written out after the filesystem scan has completed, This causes a delay in output and requires significantly more memory for large directory trees. The binary format (see -O) does not have this problem and supports efficient exporting with any number of threads.

These options affect behavior when exporting to file with the -o or -O options.

-c, --compress, --no-compress

Enable or disable Zstandard compression when exporting to JSON (see -o).

--compress-level num

Set the Zstandard compression level when using -O or -c. Valid values are 1 (fastest) to 19 (slowest). Defaults to 4.

--export-block-size num

Set the block size, in kibibytes, for the binary export format (see -O). Larger blocks require more memory but result in better compression efficiency. This option can be combined with a higher --compress-level for even better compression.

Accepted values are between 4 and 16000. The defaults is to start at 64 KiB and then gradually increase the block size for large exports.

-0

Don't give any feedback while scanning a directory or importing a file, except 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

Write progress information to the terminal, but don't open a full-screen ncurses interface. 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 usually a better choice.

-2

Show 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 updates the screen 10 times a second by default (with --fast-ui-updates ), this can be decreased to once every 2 seconds with -q or --slow-ui-updates. This option can be used to save bandwidth over remote connections. This option has no effect in combination with -0.

--enable-shell, --disable-shell

Enable or disable shell spawning from the file 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 file 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 (KiB, MiB, etc).

--disk-usage, --apparent-size

Select whether to display disk usage (default) or apparent sizes. Can also be toggled in the file browser with the 'a' key.

--show-hidden, --hide-hidden

Show (default) or hide "hidden" and excluded files. Can also be toggled in the file browser with the 'e' key.

--show-itemcount, --hide-itemcount

Show or hide (default) the item counts column. Can also be toggled in the file browser with the 'c' key.

--show-mtime, --hide-mtime

Show or hide (default) the last modification time column. Can also be toggled in the file 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 file browser with the 'g' key.

--show-percent, --hide-percent

Show (default) or hide the relative size percent column. Can also be toggled in the file browser with the 'g' key.

--graph-style hash | half-block | eighth-block

Change the way that the relative size bar column is drawn. Recognized values are hash to draw ASCII '#' characters (default and most portable), half-block to use half-block drawing characters or eighth-block to use eighth-block drawing characters. Eighth-block characters are the most precise but may not render correctly in all terminals.

--shared-column off | shared | unique

Set to off to disable the shared size column for directories, shared (default) to display shared directory sizes as a separate column or unique to display unique directory sizes as a separate column. These options can also be cycled through in the file browser with the 'u' 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 name can be suffixed with -asc or -desc to change the order to ascending or descending, respectively. For example, --sort=name-desc to sort by name in descending order.

--enable-natsort, --disable-natsort

Enable (default) or disable natural sort when sorting by file name.

--group-directories-first, --no-group-directories-first

Sort (or not) directories before files.

--confirm-quit, --no-confirm-quit

Require a confirmation before quitting ncdu. Can be 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 off | dark | dark-bg

Set the 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 off.