dtdinst software package provides XML DTD to XML instance format converter, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install dtdinst
dtdinst is installed in your system.
Make ensure the dtdinst package were installed using the commands given below,
$ sudo dpkg-query -l | grep dtdinst *
You will get with dtdinst package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Text Processing |
| Package | dtdinst |
| Version | 20131210+dfsg+1-1 |
| Description | XML DTD to XML instance format converter |
| Sub Section | Text |