How to Install SeaMonkey on Linux Mint 21 or 20

The SeaMonkey project is an open-source internet application suite that provides browser, chat, email management, and web development tools in a single solution. In the following tutorial, you will learn how to install SeaMonkey on Linux Mint 21 or Linux Mint 20 desktop with the official Ubuntuzilla Repository APT repository using the command line terminal and instructions on updating and removing the software in the future if required.

Update Linux Mint

Before proceeding with the tutorial, ensuring your system is up-to-date with all existing packages is good.

sudo apt update

Optionally, you can list the updates for users who require review or are curious.

sudo apt --list upgradable

Proceed to upgrade any outdated packages using the following command.

sudo apt upgrade

Install SeaMonkey

The first and easiest method is to install SeaMonkey using the source APT repository.

First, install the required packages.

sudo apt install dirmngr software-properties-common apt-transport-https -y

For users who have not previously imported a GPG key from the Ubuntu keyserver, the command line terminal will often have issues importing GPG keys from LaunchPAD PPAs because the directories are not created. This is an easy fix. Use the following command that will, in turn, generate the directories.

sudo gpg --list-keys

Example output:

gpg: directory '/root/.gnupg' created
gpg: keybox '/root/.gnupg/pubring.kbx' created
gpg: /root/.gnupg/trustdb.gpg: trustdb created

Next, import the GPG key required to verify the authenticity of the packages as follows.

sudo gpg --no-default-keyring --keyring /usr/share/keyrings/ubuntuzilla.gpg --keyserver --recv-keys 2667CA5C

Example output:

joshua@linux-mint:~$ sudo gpg --no-default-keyring --keyring 

/usr/share/keyrings/ubuntuzilla.gpg --keyserver --recv-keys 2667CA5C
gpg: keybox '/usr/share/keyrings/ubuntuzilla.gpg' created
gpg: key B7B9C16F2667CA5C: public key "Daniel Folkinshteyn (Ubuntuzilla signing key) <>" imported
gpg: Total number processed: 1
gpg:               imported: 1

Now import the APT repository using the following command.

printf 'deb [signed-by=/usr/share/keyrings/ubuntuzilla.gpg] all main\n' | sudo tee /etc/apt/sources.list.d/ubuntuzilla.list

The above command works for both Linux Mint 21.xx and Linux Mint 20.xx.

Run a quick APT update to reflect the newly added APT source.

sudo apt update

Lastly, install SeaMonkey using the following command.

sudo apt install seamonkey-mozilla-build

Launch SeaMonkey Internet Suite

The best method to launch SeaMonkey Internet Suite is the application icon.

Taskbar > Show Applications > Mozilla Build of SeaMonkey


Alternatively, you may want to use it for applications quite frequently. Right-click the icon and add it to favorites, making the icons appear on the taskbar.

Once you open the suite, you will be prompted to set SeaMonkey as the default client for various items such as browser, email, newsgroups, etc.


Congratulations, you have learned how to install SeaMonkey.

Additional Commands & Tips

Update SeaMonkey

Next are the commands to run in your terminal to check for updates. These commands will blanket-check all installed packages on your system that match the installation package manager.

sudo apt update && sudo apt upgrade

Remove (Uninstall) SeaMonkey

First, remove the internet suite using the following command for userswhot no longer wish to have SeaMonkey installed.

sudo apt install seamonkey-mozilla-build --purge

Users that will no longer require the APT import repository since you will not use it again can safely remove it, which is good housekeeping and security best practices.

sudo rm /etc/apt/sources.list.d/ubuntuzilla.list

Optionally, you can remove the GPG as well with the following command.

sudo rm /usr/share/keyrings/ubuntuzilla.gpg


SeaMonkey is an excellent option for a free, open-source internet suite. The tutorial has demonstrated how to import the official repository using CLI commands and install the software directly using the APT package manager, ensuring you will have the suite up-to-date whenever an update arrives on the third-party repository.

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