jing software package provides RELAX NG validator, you can install in your Ubuntu 12.04 LTS (Precise Pangolin) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install jing
jing is installed in your system.
Make ensure the jing package were installed using the commands given below,
$ sudo dpkg-query -l | grep jing *
You will get with jing package name, version, architecture and description in a table
| Distro | Ubuntu 12 04 lts precise pangolin |
| Section | Text Processing |
| Package | jing |
| Version | 20091111-4ubuntu1 |
| Description | RELAX NG validator |
| Sub Section | Text |