1.
if has('win32') " or has('win64')
" for Windows
elif has('mac') " or has('macunix')
" for Mac
else
" for others
endif
if has('ruby')
" using ruby interface
endif

2.
if filereadable(expand('~/.vimrc.local'))
source ~/.vimrc.local
endif

3.
:edit $MYVIMRC
:w
:source $MYVIMRC

4.
autocmd BufEnter * let b:count += 1

5.
autocmd!
autocmd BufEnter * let b:count += 1

6.
augroup vimrc
autocmd!
augroup END
autocmd vimrc BufEnter * let b:count += 1
augroup vimrc
autocmd BufLeave * let b:count += 1
augroup END

7.
set guioptions&
set guioptions-=T
set guioptions-=m

8.
function! Hoge()
echo "hoge"
endfunction
command! Fuga echo "fuga"

9.
nnoremap <Space> :<C-u>echo "hoge"<CR>

10.
set sts=4 sw=4 ts=4
augroup vimrc
autocmd Filetype ruby
setlocal sts=2 sw=2 ts=2
augroup END

11.
let g:vimrc_local_finish = 1