First I set up my default terminal as the zsh and I added omz and the powerlevel10k theme o it and I remember that I followed some tutorial steps and it ended me up with this terminal that is shown here which contains some machine information like the current RAM usage. these settings were bothering me cause the icons were disabled and shown as a weird square and then I deleted all files of powerlevel10k and reset the terminal back to its default. Now I managed to solve the icons issue but I couldn't remember how to make my terminal showing RAM.