Certain commands dont work . How do I fix it?

I've successfully managed to install Ubuntu server 18.04. Most of my sudo commands work fine, however, I am having issues running the cd/cp commands. ie: whenever I type cd/ I get:

-bash: cd/: No such file or directory.

The same thing happens when I type cat auth.log and when I use q to quit. The program suggested installing python, which I did; but still no results. Please advise, thank you.

Let's divide this to subquestions:

whenever I type 'cd/' I get '-bash: cd/: No such file or directory'.

When we whats the usage of the command cd (cd --help) we will found as follows:

cd: cd [-L|[-P [-e]] [-@]] [dir]

Change the shell working directory.

What you are mistaking is that you are missing a space after using command cd and the system is recognizing this as command cd/ not a command cd /. This will cause the error you are mentioning.

We can do the same for using cat, be first sure to use cat --help to find out how this commands has to be used, or google it.

Be sure you are using an existing file otherwise, the cat will output

cat: auth.log: No such file or directory

Which you may misunderstand as cat is not existing.

cd, as well as cat, are default Ubuntu commands which are always present, until you uninstall them, which I am not sure if it's possible.

I believe the same applies for 'q' which is just closing output on the terminal if needed.

I would recommend looking at the basic Ubuntu usage docs they are providing link for the beginning!