php-xml-dtd software package provides Parsing of DTD files and DTD validation of XML files, 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 php-xml-dtd
php-xml-dtd is installed in your system.
Make ensure the php-xml-dtd package were installed using the commands given below,
$ sudo dpkg-query -l | grep php-xml-dtd *
You will get with php-xml-dtd package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | PHP |
| Package | php-xml-dtd |
| Version | 0.5.2+dfsg1-3 |
| Description | Parsing of DTD files and DTD validation of XML files |
| Sub Section | PHP |