I have this NAS : TerraMaster and I see that I could connect to this via SSH.
So I did this and want to see the processor activity with htop. I try to install it, with apt-get, yum etc... But none of this working 'command not found'.
uname -a say this :
Linux nathan30 4.0.0 #304 SMP Fri Jan 6 18:16:22 CST 2017 x86_64 GNU/Linux
By just looking at their website, you can see that TerraMaster has its own OS TerraMaster OS: http://www.terra-master.com/html/en/article_list_160.html
This question on stackoverflow might help you: http://unix.stackexchange.com/questions/329554/install-a-package-manager-on-a-terramaster-nas