When I type
apt-get install
or
apt-get update
on shell, kernel does not recognize it. What can I do for that?
apt-get is not part of openSUSE (and it is not part of kernel too). It is just an application.
Under openSUSE, you may use zypper instead.
zypper install ...
zypper up
Well, you could do this, but I strongly suggest that you don’t. If you go outside of the mainstream of SuSE usage, which this would be, your chances of getting useful help decrease dramatically.
Zypper Usage
Or,
there’s YaST, GUI or CLI