Editing Su-write

{{TipImported
|id=975
|previous=974
|next=976
|created=August 18, 2005
|complexity=basic
|author=Bernard Pratz
|version=6.0
|rating=7/3
|category1=
|category2=
}}
Sometimes you modify a file, for example from the <tt>/etc</tt> directory, then when you try to save the file, you get a permission-denied error. This tip presents some suggestions for using sudo from with Vim, so you can successfullly write the file with temporary privileges.

Of course, this tip has to be used with caution, as it gets you more power.

==Suggestion 1==
If you find you do not have permission to perform <tt>:w</tt>, use the following:
<pre>
:w !sudo tee % > /dev/null
</pre>

You can make a command so <tt>:W</tt> invokes sudo:
<pre>
command W w !sudo tee % > /dev/null
</pre>

Or, if you know about the problem beforehand:
<pre>
sudoedit path_to_file
sudo -e path_to_file
</pre>

==Suggestion 2==
The following function saves the current file to a temporary file, then copies the new file to replace the original. It preserves the modes of the original file, though it is being rewritten.
<pre>
function Suedit()
  let fname=tempname()
  exec 'w' fname
  let writetarget=shellescape(expand("%:p"))
  let owner=shellescape(system('stat --printf=%U:%G ' . writetarget))
  let modes=system('stat --printf=c%a ' . writetarget)
  exec '!sudo cp' shellescape(fname) writetarget
  exec '!sudo chmod' modes writetarget
  exec '!sudo chown' owner writetarget
endfunction
</pre>

'''Warning''' There is no check for symlinks. A symlink would be removed and replaced by a file with the symlink's modes, which are 777.

==Suggestion 3==
Here is a mapping to save to a <tt>/tmp</tt> file, then overwrite the working file.
<pre>
nnoremap <leader>es :w! /tmp/sudoSave \| let $fileToSave=expand('%') \| let $fileToSaveBackup=expand('%').'~' \| !sudo cp $fileToSave $fileToSaveBackup && sudo cp /tmp/sudoSave $fileToSave<CR><ESC>:e!<CR>
</pre>

'''Warning''' This command will reload the file; you will lose the modifications history (undo will not work, although it does keep a backup).

Note that a backup is made, even when '<tt>nobackup</tt>' is set.

==Comments==
Use {{script|id=729}} which has had more testing.

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