I am tired of losing my vi configuration every time I switch computers and forget about it.

.vimrc

" with thanks to https://github.com/amix/vimrc/blob/master/vimrcs/basic.vim

" highlighting!
syntax enable

" spaces not tabs
set expandtab

" tabs should be 4 spaces not 8:
set tabstop=4
set shiftwidth=4

set autoindent
set ruler

" highlight matching brackets
set showmatch

" set wordwrap:
set wm=5

" don't bother with swapfiles
set noswapfile

" Enable 256 colors palette in Gnome Terminal
if $COLORTERM == 'gnome-terminal'
    set t_Co=256
endif

" Display the current mode:
set showmode

" teach backspace about linewrap
set backspace=eol,start,indent
set whichwrap+=<,>,h,l

" ignore case in search
set ignorecase

" Delete trailing white space on save
fun! CleanExtraSpaces()
    let save_cursor = getpos(".")
    let old_query = getreg('/')
    silent! %s/\s\+$//e
    call setpos('.', save_cursor)
    call setreg('/', old_query)
endfun