---
name: "dtddiff"
section: "1"
platform: "linux"
package: "perlsgml"
version: "1:19970918-12.2"
release: "Debian 5.0 (Lenny)"
platforms: ["linux"]
url: "https://new.carta.tech/dtddiff"
---

# dtddiff(1)

show differences between two SGML Document Type Definitions (DTDs)

## NAME

dtddiff — show differences between two SGML Document Type Definitions (DTDs)

## SYNOPSIS

**dtddiff** \[options\] *dtd1*   *dtd2*

## DESCRIPTION

**dtddiff** shows differences between the two DTDs whose  filenames are provided as arguments.  Output goes to STDOUT and is in  ASCII format.  Warnings,  for  example,  notes about  declarations  which    are ignored in the output, are sent to STDOUT.

There are three main sections of the output:

- New Elements/Attributes

  includes elements which  are  in the  second  DTD    but  not  the first, and elements which  are  present  in  both    DTDs  but  have  new attributes in the second DTD.

- Old/removed Elements/Attributes

  includes elements which were part of the first DTD   but not the second,  and elements  with  attributes  which were in the   first DTD but not the second.

- Content Rule Differences

  lists, for each  element  which has either changed or   been added in the second DTD, the content rule in each DTD.

**dtddiff** is one of a  suite  of  tools available   in  the perlSGML  package, which together help one inspect, study,  and edit if necessary, an SGML Document  Type  Definitions  (DTD).    The   package   was   written   by   Earl   Hood  (ehood@medusa.acs.uci.edu).

This manual page was written for the **Debian GNU/Linux** distribution  because the original program does not have a manual page.  Instead, it has documentation in the **HTML**       format; see below.

## OPTIONS

This program takes the following command-line options:

- **-catalog**

  - **-compact**

  Generate a compact listing; this is the default.

- **-help**

  Print a brief usage description. No other action is   performed.

- **-nocompact**

  Generate a long listing.

## SEE ALSO

dtd2html (1), dtdtree (1), dtdview (1), and stripsgml (1).  These commands, as well as perlSGML's library of Perl modules   for parsing of the SGML DTD's are documented fully by       *The perlSGML Manual (link to URL http://www.oac.uci.edu/indiv/ehood/perlSGML/doc/html/perlSGML.html)* .

## AUTHOR

This manual page was written by Susan G. Kleinmann sgk@debian.org for  the **Debian GNU/Linux** system (but may be used by others).

Permission is granted to copy, distribute and/or modify  this document under the terms of the GNU Free  Documentation License, Version 1.1 or any later version  published by the Free Software Foundation; with no Invariant  Sections, no Front-Cover Texts and no Back-Cover Texts.  A copy  of the license can be found under  **/usr/share/common-licenses/FDL**.