Why doesn't Vim show number lines after editing .vimrc

Question

I have edited my .vimrc file to include the following line:

set number

I've saved the file and closed out vim entirely and when reopening files theres still no line numbers.

Here's the entire file which is located at /usr/share/vim/vimrc

" Configuration file for vim
set modelines=0     " CVE-2007-2438

" Normally we use vim-extensions. If you want true vi-compatibility
" remove change the following statements
set nocompatible    " Use Vim defaults instead of 100% vi compatibility
set backspace=2     " more powerful backspacing

" Don't write backup file if vim is being called by "crontab -e"
au BufWrite /private/tmp/crontab.* set nowritebackup
" Don't write backup file if vim is being called by "chpass"
au BufWrite /private/etc/pw.* set nowritebackup

set number

Answer 1

After you edited your vimrc file(either the one of system default or the one in your home directory), you should use source command as followings to read it in and make those configurations valid on current session.

:source ~/.vimrc

or

:source  /usr/share/vim/vimrc