dcmdump(1)

🎀 NAME 🎀

okay so this is the dcmdump(1) manual page from OFFIS DCMTK, and dcmdump is literally the utility that dumps DICOM file and data set contents to stdout in textual form 💖.

✨ SYNOPSIS ✨

dcmdump [options] dcmfile-in...

🦋 DESCRIPTION 🦋

dcmdump dumps the contents of a DICOM file (file format or raw data set) to stdout in textual form, bestie. Attributes with very large value fields (e.g. pixel data) can be described as (not loaded). String value fields will be delimited with square brackets ([]). Known UIDs will be displayed by their names prefixed by an equals sign (e.g. =MRImageStorage) unless this mapping would be explicitly switched off. Empty value fields are described as (no value available).

If dcmdump reads a raw data set (DICOM data without a file format meta-header) it will attempt to guess the transfer syntax by examining the first few bytes of the file. It is not always possible to correctly guess the transfer syntax, and it is better to convert a data set to a file format whenever possible (using the dcmconv utility). It is also possible to use the -f and -t[ieb] options to force dcmdump to read a dataset with a particular transfer syntax.

🫶 lowkey important: the guessing thing is a whole vibe, but it is not a guarantee. converting with dcmconv is the safer main-character move.

💅 PARAMETERS 💅

• dcmfile-in — DICOM input file or directory to be dumped (- for stdin)

🔥 OPTIONS 🔥

🌸 general options 🌸

• -h, --help — print this help text and exit
• --version — print version information and exit
• --arguments — print expanded command line arguments
• -q, --quiet — quiet mode, print no warnings and errors
• -v, --verbose — verbose mode, print processing details
• -d, --debug — debug mode, print debug information
• -ll, --log-level — [l]evel: string constant; the valid values are fatal, error, warn, info, debug, trace, and you use level l for the logger
• -lc, --log-config — [f]ilename: string; use config file f for the logger

💜 input options 💜

input file format

• +f, --read-file — read file format or data set (default)
• +fo, --read-file-only — read file format only
• -f, --read-dataset — read data set without file meta information

input transfer syntax

• -t=, --read-xfer-auto — use TS recognition (default)
• -td, --read-xfer-detect — ignore TS specified in the file meta header
• -te, --read-xfer-little — read with explicit VR little endian TS
• -tb, --read-xfer-big — read with explicit VR big endian TS
• -ti, --read-xfer-implicit — read with implicit VR little endian TS

input files

• +sd, --scan-directories — scan directories for input files (dcmfile-in)
• +sp, --scan-pattern — [p]attern: string (only with --scan-directories); pattern for filename matching (wildcards)

# possibly not available on all systems

• -r, --no-recurse — do not recurse within directories (default)
• +r, --recurse — recurse within specified directories

long tag values

• +M, --load-all — load very long tag values (default)
• -M, --load-short — do not load very long values (e.g. pixel data)
• +R, --max-read-length — [k]bytes: integer (4..4194302, default: 4); set threshold for long values to k kbytes

parsing of file meta information

• +ml, --use-meta-length — use file meta information group length (default)
• -ml, --ignore-meta-length — ignore file meta information group length

parsing of odd-length attributes

• +ao, --accept-odd-length — accept odd length attributes (default)
• +ae, --assume-even-length — assume real length is one byte larger

handling of explicit VR

• +ev, --use-explicit-vr — use explicit VR from dataset (default)
• -ev, --ignore-explicit-vr — ignore explicit VR (prefer data dictionary)

handling of non-standard VR

• +vr, --treat-as-unknown — treat non-standard VR as unknown (default)
• -vr, --assume-implicit — try to read with implicit VR little endian TS

handling of undefined length UN elements

• +ui, --enable-cp246 — read undefined len UN as implicit VR (default)
• -ui, --disable-cp246 — read undefined len UN as explicit VR

handling of defined length UN elements

• -uc, --retain-un — retain elements as UN (default)
• +uc, --convert-un — convert to real VR if known

handling of private max-length elements (implicit VR)

• -sq, --maxlength-dict — read as defined in dictionary (default)
• +sq, --maxlength-seq — read as sequence with undefined length

handling of wrong delimitation items

• -rd, --use-delim-items — use delimitation items from dataset (default)
• +rd, --replace-wrong-delim — replace wrong sequence/item delimitation items

handling of illegal undefined length OB/OW elements

• -oi, --illegal-obow-rej — reject dataset with illegal element (default)
• +oi, --illegal-obow-conv — convert undefined length OB/OW element to SQ

handling of VOI LUT Sequence with OW VR and explicit length

• -vi, --illegal-voi-rej — reject dataset with illegal VOI LUT (default)
• +vi, --illegal-voi-conv — convert illegal VOI LUT to SQ

handling of explicit length pixel data for encaps. transfer syntaxes

• -pe, --abort-expl-pixdata — abort on explicit length pixel data (default)
• +pe, --use-expl-pixdata — use explicit length pixel data

general handling of parser errors

• +Ep, --ignore-parse-errors — try to recover from parse errors
• -Ep, --handle-parse-errors — handle parse errors and stop parsing (default)

other parsing options

• +st, --stop-after-elem — [t]ag: "gggg,eeee" or dictionary name; stop parsing after element specified by t
• +sb, --stop-before-elem — [t]ag: "gggg,eeee" or dictionary name; stop parsing before element specified by t

# only considers elements on main dataset level and also # works if the given tag is not present in the file

automatic data correction

• +dc, --enable-correction — enable automatic data correction (default)
• -dc, --disable-correction — disable automatic data correction

bitstream format of deflated input

• +bd, --bitstream-deflated — expect deflated bitstream (default)
• +bz, --bitstream-zlib — expect deflated zlib bitstream

🌈 processing options 🌈

specific character set

• +U8, --convert-to-utf8 — convert all element values that are affected by Specific Character Set (0008,0005) to UTF-8

# requires support from an underlying character encoding library # (see output of --version on which one is available)

⭐ output options ⭐

printing

• +L, --print-all — print long tag values completely
• -L, --print-short — print long tag values shortened (default)
• +T, --print-tree — print hierarchical structure as a simple tree
• -T, --print-indented — print hierarchical structure indented (default)
• +F, --print-filename — print header with filename for each input file
• +Fs, --print-file-search — print header with filename only for those input files that contain one of the searched tags

mapping

• +Un, --map-uid-names — map well-known UID numbers to names (default)
• -Un, --no-uid-names — do not map well-known UID numbers to names

quoting

• +Qn, --quote-nonascii — quote non-ASCII and control chars as XML markup
• +Qo, --quote-as-octal — quote non-ASCII and control chars as octal numbers
• -Qn, --print-nonascii — print non-ASCII and control chars (default)

color

• +C, --print-color — use ANSI escape codes for colored output
• -C, --no-color — do not use any ANSI escape codes (default)

error handling

• -E, --stop-on-error — do not print if file is damaged (default)
• +E, --ignore-errors — attempt to print even if file is damaged

searching

• +P, --search — [t]ag: "gggg,eeee" or dictionary name; print the textual dump of tag t; this option can be specified multiple times (default: the complete file is printed)
• +s, --search-all — print all instances of searched tags (default)
• -s, --search-first — only print first instance of searched tags
• +p, --prepend — prepend sequence hierarchy to printed tag, denoted by: (gggg,eeee).(gggg,eeee).* (only when used with --search)
• -p, --no-prepend — do not prepend hierarchy to tag (default)

writing

• +W, --write-pixel — [d]irectory: string; write pixel data to a .raw file stored in d (little endian, filename created automatically)

🌟 NOTES 🌟

Adding directories as a parameter to the command line only makes sense if option --scan-directories is also given. If the files in the provided directories should be selected according to a specific name pattern (e.g. using wildcard matching), option --scan-pattern has to be used. Please note that this file pattern only applies to the files within the scanned directories, and, if any other patterns are specified on the command line outside the --scan-pattern option (e.g. in order to select further files), these do not apply to the specified directories.

🧚 LOGGING 🧚

The level of logging output of the various command line tools and underlying libraries can be specified by the user. By default, only errors and warnings are written to the standard error stream. Using option --verbose also informational messages like processing details are reported. Option --debug can be used to get more details on the internal activity, e.g. for debugging purposes. Other logging levels can be selected using option --log-level. In --quiet mode only fatal errors are reported. In such very severe error events, the application will usually terminate. For more details on the different logging levels, see documentation of module "oflog".

In case the logging output should be written to file (optionally with logfile rotation), to syslog (Unix) or the event log (Windows) option --log-config can be used. This configuration file also allows for directing only certain messages to a particular output stream and for filtering certain messages based on the module or application where they are generated. An example configuration file is provided in <etcdir>/logger.cfg.

🎀 COMMAND LINE 🎀

Okay bestie, so every single command line tool in this family speaks the same little notation language, and honestly it's giving very consistent of them:

• Square brackets [ ] mean the value inside is optional — like, 0 to 1 of them, your call.
• Three trailing dots ... mean "hey, you can pile on multiple values" — 1 to n.
• Combine both? That's 0 to n values, the full glow-up.

Command line options and parameters are told apart by a leading sign, respectively: options get a + or - in front, parameters don't. ✨

Usually the order and position of command line options is completely arbitrary — they can show up literally anywhere, no cap. But if two options are mutually exclusive, the one that appears rightmost wins. That's just how it is, and it totally conforms to the standard evaluation rules of common Unix shells. 💅

Also! You can drop one or more command files in by prefixing a filename with an @ sign (like @command.txt). That command argument gets swapped out for the content of the corresponding text file — before any further evaluation happens. 🫶

Heads up, because this matters: multiple whitespaces get treated as a single separator, unless they appear between two quotation marks. And a command file cannot contain another command file. Nested command-file-ception is simply not a thing. 🚫

This simple but effective approach lets you summarize common combos of options/parameters and dodges those longish, confusing command lines everyone hates. There's an example waiting for you in the file <datadir>/dumppat.txt. Go look, it's cute. 💖

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🌸 ENVIRONMENT 🌸

So dcmdump will attempt to load DICOM data dictionaries specified in the DCMDICTPATH environment variable. But by default — meaning if DCMDICTPATH isn't set at all — the file <datadir>/dicom.dic gets loaded instead, unless the dictionary is built into the application (which is the default for Windows). 🪟

The default behavior should be preferred, bestie. Only reach for DCMDICTPATH when you actually need alternative data dictionaries. Like, don't touch it just to touch it. 🙈

The DCMDICTPATH variable has the same format as the Unix shell PATH variable — a colon (":") separates entries. On Windows systems, it's a semicolon (";") doing the separating instead. The data dictionary code will attempt to load each file specified in DCMDICTPATH, and it is an error if no data dictionary can be loaded. 💀

Depending on the command line options you specify, dcmdump will also attempt to load character set mapping tables. This happens when DCMTK was compiled with the oficonv library (which is the default ✨) and the mapping tables are not built into the library (the default when DCMTK uses shared libraries).

The mapping table files are expected in DCMTK's <datadir>. You can point at a different location with the DCMICONVPATH environment variable. But real talk: if you specify a different location, those mapping tables also replace any built-in tables. So like, it's a whole swap, not a merge. 👑

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🔥 SEE ALSO 🔥

• dump2dcm(1)
• dcmconv(1)

Go read those too, they're icons in their own right. 🫶

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⭐ COPYRIGHT ⭐

Copyright (C) 1994-2026 by OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany. 🥹

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And that's a wrap, bestie! 💖 This little masterpiece is Version 3.7.1, dated Sat Oct 17 2026 09:34:01 — go forth and dump those DICOMs, you absolute main character. 🦋👑✨