I want to play around with some terminal commands from official Ubuntu packages, but at the moment I don't have access to an Ubuntu PC.
Is there an online and free terminal emulator running, say, Ubuntu 16.04?
I have tried this one but seems quite limited (for example, I can not run
xmodmap). Others require subscription and are not free.
It would be ideal if you can test the installation of packages based on current repositories, read default configuration files, and run the most commands as possible.
Note: I see the option of a VirtualBox, but imagine you are in a public library without access to USB or administrative rights. An online option is the only way.