rpn is a free and open source math functional language app for Linux. rpn uses the reverse postfix polish notation for the calculation. It is written in C++ and released under GNU Lesser General Public License v3.0. It is is dynamically linked to GNU MP and GNU MPFR. You can read and check the rpn reference manual here.
How to Install rpn on Ubuntu Linux
rpn is available as a flatpak app from the remote flathub. First install flatpak and flathub on your system and restart it after the installation. You can install flatpak and flathub using below link.
Open the terminal command-line software using the ctrl+alt+t keys and run below rpn flatpak install command.
flatpak install flathub fr.rubet.rpn
Then run below flatpak command. It will run rpn on your terminal app.
flatpak run fr.rubet.rpn
You you can also uninstall it using below command.
sudo flatpak uninstall fr.rubet.rpn