The simplest way to start Vim in private mode

Question

I want to be able to easily start Vim in a private mode. Let's define a private mode as one that utilizes this set of commands:

set history=0
set nobackup
set nomodeline
set noshelltemp
set noswapfile
set noundofile
set nowritebackup
set secure
set viminfo=""

Let me know if you can think of any additional commands suitable for the private mode.

The point is I cannot think of any short and easy way to start Vim with this setup.

Here are some ideas I've come up with:

1. Load .vimrcprivate instead of .vimrc

   You can simply put all the necessary commands into .vimrcprivate and start Vim like this:

   vim -u .vimrcprivate
   

2. Define and call a Private() function

   Another idea add a code like this to your .vimrc:

   function Private()
       " set of commands here
   endfunction
   

   and then you are able to start Vim in a private mode like this:

    vim -c 'call Private()'
   

3. Use a variable to trigger the setting up of your commands

   It is quite similar to the second solution. Just add

   if exists('privatemode')
       " set of commands here
   endif
   

   to your .vimrc and then start Vim using

   vim -c 'let privatemode=1'
   

   which is neither smart nor short.

4. Add an alias to your .bashrc (or to any other .*rc file your shell is using)

   For example:

   alias vimprivate="vim +\"set history=0\" +\"set nobackup\" +\"set nomodeline\"\
       +\"set noshelltemp\" +\"set noswapfile\" +\"set noundofile\"\ 
       +\"set nowritebackup\" +\"set secure\" +\"set viminfo=\"\"\""
   

   which is awful. I don't like it.

5. Use an environmental variable

   Just run VIM_PRIVATE=1 vim and add

   if $VIM_PRIVATE
       " set of commands here
   endif
   

   to your .vimrc.

6. Some magic (from a comment by Carpetsmoker in this thread)

   Carpetsmoker says in this comment that

   I would not recommend using a separate vimrc file, for the simple reason > that it's so easy to forget. Something like this autocmd: au BufRead * if &cryptmethod != "" | setlocal nobackup noundofile ... | endif should do the magic for you, and it's impossible to forget.

   However I've got no idea how this magic works yet.

---

Have you got any idea?

The perfect solution would be vim -private or vim +Private however:

• I am quite sure you cannot add you own custom command line options like -private.
• when it comes to +Private I was unable to find it online.

Answer 1

Well, a bit belated but to respond to:

6. Some magic (from a comment by Carpetsmoker in this thread)

My general idea was that you always want to start "private mode" if you're using an encrypted file, so this autocommand will do that for you:

au BufRead * if &key!= ""
    \ | setlocal history=0 nobackup nomodeline noshelltemp noswapfile noundofile nowritebackup secure viminfo=""
    \ | endif

Basically, every time a file is read from disk it checks if the key setting is set (this is where your passphrased is stored), and if it is, it sets you settings. See :help autocommand for a general overview on how autocommands work.

The advantage to this is that can't forget to use it.

Of course, it requires that the file is encrypted. If it isn't, nothing is done. But not all is lost, we can use a filename to indicate a file is private, for example:

au BufRead *.private setlocal ...

Would mark all files ending with .private as such.

If you want to randomly open files in "private" mode, then I would recommend using a simple shell alias, e.g.:

alias vimprivate='vim -c "source ~/.vim/private"

And ~/.vim/private would contain:

setlocal history=0 nobackup nomodeline noshelltemp noswapfile noundofile nowritebackup secure viminfo=""

Why not -u? Well, this way you have your own settings and the "private" settings. You can also combine the two with:

au BufRead * if &key!= "" | source ~/.vim/private | endif

Answer 2

According to Vim documentation (:help -c) there can only be a maximum of 10 +{command}, -c {command} and -S {file} option arguments combined when starting Vim, and they execute _after_ the first file is read.

The --cmd {command} option allows an additional 10 commands to be executed before processing any vimrc file, but bear in mind that any settings can be overridden by vimrc.

Therefore I prefer to set Vim options early, and avoid any need for environment variable or scripting logic. Also, plugins may be doing dodgy things so it is better to not load any.

The most secure invocation method I can think of is using aliases in ~/.bashrc with a simple and to-the-point vimrcprivate file:

# Secure Vim
alias vimsec="vim -N -n -i NONE -u ~/.vimrcprivate"
alias gvimsec="g$(alias vimsec | sed -e "s/-u/-U/" -e "s/\(.*\)'\(.*\)'/\2/")"

Answer 3

A slightly neater looking alias:

alias vimprivate='vim -u NONE -c "setlocal history=0 nobackup nomodeline noshelltemp noswapfile noundofile nowritebackup secure viminfo=\"\""'