erc software package provides an IRC client for Emacs, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install erc
erc is installed in your system.
Make ensure the erc package were installed using the commands given below,
$ sudo dpkg-query -l | grep erc *
You will get with erc package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Network |
| Package | erc |
| Version | 5.3-1ubuntu2 |
| Description | an IRC client for Emacs |
| Sub Section | Net |