How to uninstall mailreader from Ubuntu
To uninstall just mailreader package itself from Ubuntu execute on terminal:
sudo apt-get remove mailreader
Uninstall mailreader and it's dependent packages
To uninstall the mailreader package and any other dependant package which are no longer needed on Ubuntu.
sudo apt-get autoremove mailreader
If you also want to delete configuration and/or data files of mailreader from Ubuntu then this will work:
sudo apt-get purge mailreader
To delete configuration and/or data files of mailreader and it's dependencies from Ubuntu then execute:
sudo apt-get autoremove --purge mailreader
mailreader package information
Simple, but powerful WWW mail reader system
Mailreader is a light and simple web based mail user agent written in Perl. The very simple configuration distinguishes it from other webmail solutions. It requires an available POP3 server on the network for normal operation, as it does not support IMAP or other means of accessing mail spools. To use Mailreader's support for Japanese you need libjcode-pm-perl installed, please ignore this suggestion otherwise. For the highly recommended use of secure connections a httpd with SSL support (like apache-ssl) is needed.
More information about apt-get remove
Advanced Package Tool, or APT, is a free software user interface that works with core libraries to handle the installation and removal of software on Debian, Ubuntu and other Linux distributions. APT simplifies the process of managing software on Unix-like computer systems by automating the retrieval, configuration and installation of software packages, either from precompiled files or by compiling source code.
apt-get is the command-line tool for handling packages, and may be considered the user's "back-end" to other tools using the APT library.
apt-get remove is identical to install except that packages are removed instead of installed. Note that removing a package leaves its configuration files on the system. If a plus sign is appended to the package name (with no intervening space), the identified package will be installed instead of removed.