Great question — answering as the UphillTech team:
It will depend on what you pretend to do with it, if is just want to read some info from your system from time to time, there are lots of commands like top (cpu process usage), ps -le (process status), lm-sensors give you a bit more info. Then you have other ones that give you info constantly on your desktop like gkrellm or conky. googling you will find a lot more options..
Full answer by Irwing: https://askubuntu.stackexchange.com/a/575422 (CC BY-SA 4.0).
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