Termux

Android is a heavily modified Linux operating systems, which means that many of the same apps and principles still work. That’s true for terminal apps as well, but they are not as common Android as you would think. Phones and tablets are not ideal as a platform for terminals, but it’s also not impossible.
Termux brings the bash and zsh shells to users for them to enjoy, allowing them to edit files with nano and vim, to access servers over SSH, to use python, to check out projects with git and subversion, and much more.
Furthermore, the packages people want to install can be downloaded with APT, which is a nice and useful feature.