Good convention is to can create your own .vimrc file in your $HOME directory, and include this line which will cause Vim to jump to the last known position in a previously edited file.
In $HOME/.vimrc, add the following lines:
" Reopen the last edited position in files
au BufReadPost * if line("'\"") > 1 && line("'\"") <= line("$") | exe "normal! g'\"" | endif
There is no need to edit the system-wide file /etc/vim/vimrc.
Creating and using your own .vimrc in your $HOME directory is also better for maintainability. The system vimrc configuration file could be updated when the Vim application package gets an update next time, or edited by someone else. Your own file in your own home-directory will be honored when you run Vim.
I actually recommend you look into all the great things you can do with your own .vimrc file. I have mine configured with tons of useful options and even a few custom functions.