How can I make vim check automatically if the file has changed externally?

Question

I usually open many files in tabs with vim -p. Is it possible to check if any of the files was changed outside of Vim since editing started?

Answer 1

Use :edit

:help :edit for more info.

Answer 2

vim usually warns me automatically if it detects an external change to a file; however, from perusing the documentation it looks like you can invoke that check manually with :checktime

Unfortunately I don't know how to disable that aforementioned automatic check to test and see if checktime does the right thing, so this answer might be completely off-base.

Answer 3

let s:pid=system("ps -p $$ -o ppid=")+0
if !exists('g:watches')
    let g:watches={}
else
    finish
endif
function! ModWatch(fname, match)
    let fname=fnamemodify(a:fname, ':p')
    if has_key(g:watches, fname)
        return
    endif
    let shellscript=
                \"while true ; do".
                \"    inotifywait ".shellescape(fname)." ; ".
                \"    kill -WINCH ".s:pid." ; ".
                \"done"
    echo shellscript
    echo shellescape(shellscript)
    let pid=system("sh -c ".shellescape(shellscript)." &>/dev/null & echo $!")+0
    call extend(g:watches, { fname : pid })
    augroup ModWatch
        execute "autocmd! BufWipeOut ".a:match
        execute "autocmd BufWipeOut ".a:match.' call DeleteWatch("'.
                    \escape(fname, '\"|').'")'
    augroup END
endfunction
function! DeleteWatch(fname)
    call system("kill ".g:watches[a:fname])
    unlet g:watches[a:fname]
endfunction
augroup ModWatch
    autocmd!
    autocmd VimResized * checktime
    autocmd BufNew * call ModWatch(expand("<afile>"), expand("<amatch>"))
augroup END

Answer 4

You can find out if the buffer in the active window is modified by running the command:

:set mod?

If it returns nomodified, then the contents of the buffer match those of the corresponding file. If it returns modified, then the buffer has unsaved changes.

By default, the status-line shows a [+] symbol if the current buffer has been modified. The status line is generally only visible if you have split windows. If you want to show the status line, even when you have just a single window, run:

:set laststatus=2

There's a good article about customizing your status line on Vim Recipes.

Answer 5

http://vim.wikia.com/wiki/Have_Vim_check_automatically_if_the_file_has_changed_externally

Answer 6

I came across an interesting find related to this question today...

Hidden in /usr/share/vim/vim71/vimrc_example.vim there is this command:

" Convenient command to see the difference between the current buffer and the
" file it was loaded from, thus the changes you made.
command DiffOrig vert new | set bt=nofile | r # | 0d_ | diffthis
        \ | wincmd p | diffthis

It will open a vimdiff-like window with the current buffer and the underlying file highlighting all of the changes between the two.