" enable syntax highlighting
syntax on
 
" Highlight redundant whitespaces and tabs.
highlight RedundantSpaces ctermbg=red guibg=red
match RedundantSpaces /\s\+$\| \+\ze\t\|\t/
 
" use 4 spaces instead of tabs
set tabstop=4
set shiftwidth=4
set expandtab
set softtabstop=4
 
" always show ^M in DOS files
set fileformats=unix