私はこんな感じ
.vimrc の最後のほう
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if has( 'autocmd' )
source $HOME/.vim/myplugin/filetype.vim " about filetype
source $HOME/.vim/myplugin/encode.vim " about encoding to save
endif
------------
encode.vim
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:autocmd BufNewFile,BufRead *.jis set fileencoding=iso-2022-jp
:autocmd BufNewFile,BufRead *.sjis set fileencoding=shift-jis
:autocmd BufNewFile,BufRead *.euc-jp set fileencoding=euc-jp
:autocmd BufNewFile,BufRead *.mozex set fileencoding=utf-8
:autocmd BufNewFile,BufRead *.elm set fileencoding=utf-8
:autocmd BufNewFile,BufRead cddbread.* set fileencoding=utf-8
:autocmd BufNewFile,BufRead *.tex set fileencoding=euc-jp