"E492: Not an editor command: PlugInstall" only when I "sudo vim"

Question

My question is a spinoff from this previous question 6 months ago, so to get more details and see how I've installed Vim Plug have a look here.

Currently I wanted to add this extension.
https://github.com/mattn/emmet-vim

Here's my .vimrc file.

  1
  2 syntax on
  3 map <F5> :source ~/.vimrc<CR>
  4
  5 set background=light       " set background = set bg
  6
  7 " colorscheme desert
  8 colorscheme elflord
  9 " colorscheme slate
 10 " colorscheme pablo
 11 " colorscheme koehler
 12 " colorscheme murphy
 13 " colorscheme industry
 14 " colorscheme torte
 15 " colorscheme default
 16 " colorscheme morning
 17 " colorscheme ron
 18 "
 19 set background=dark        " Setting up background=dark, makes text lighter
 20 "
 21 "
 22 "
 23 set nocompatible           " Set compatibility to Vim only
 24 set wildmenu               " Enable Vim's builtin auto completion engine
 25 set ignorecase          " By default searching in Vin using / command is case-sensitive.
 26                      " Use 'set ignorecase' to set searching in Vim case insensitive.
 27                      " Use 'set smartcase' to make search case insensitive if you type the search pattern using lower case only.
 28                            "
 29 set number              " Show line numbers.  Opposite is set nonumber.
 30 "
 31 set shiftwidth=3        " Set tabulator size to 4
 32 set tabstop=3           " Set tabulator size to 4
 33 set softtabstop=3       " Set tabulator size to 4
 34 "
 35 set wrap              " Automatically wrap text that extends beyond the screen length
 36 "
 37 set laststatus=2        " Show status bar
 38 "
 39 set encoding=utf-8         " Force encoding
 40 set list             " Shows hidden characters
 41 set nolist              " Hide invisible characters
 42 "
 43 "
 44 "
 45                      " Call the .vimrc.plug file
 46 if filereadable(expand("~/.vimrc.plug"))
 47     source /home/michal/.vimrc.plug
 48 endif
 49

And here's my .vimrc.plug file:

  1 " Plugins will be downloaded under the specified directory.
  2 call plug#begin('~/.vim/plugged')
  3
  4 " Fugitive Vim Github Wrapper
  5 Plug 'tpope/vim-fugitive'
  6 " Emmet Vim
  7 Plug 'mattn/emmet-vim'
  8
  9 call plug#end()

Both of these files are located in my user directory /home/michal/, like so:

michal@ubuntu:~$ ls -lah /home/michal/.vim*
-rw------- 1 michal michal  20K Jun 21 23:23 /home/michal/.viminfo
-rw-rw-r-- 1 michal michal 1.7K Jun 21 23:12 /home/michal/.vimrc
-rw-rw-r-- 1 michal michal  203 Jun 21 23:09 /home/michal/.vimrc.plug
-rw-rw-r-- 1 michal michal  110 Dec 14  2022 /home/michal/.vimrc.plug.bak
-rw-r--r-- 1 root   root    12K Jun 21 23:53 /home/michal/.vimrc.plug.swp

When I execute the command :PlugInstall while I run Vim as michal user, everything works fine.

But when I open Vim using sudo vim and then try to run :PlugInstall, I get E492: Not an editor command: PlugInstall error.

Why is that?

I'm using Vim 95/100 times using sudo vim filename, therefore I need all those plugins I install with Vim Plug, to work in sudo mode.

Answer 1

Rather than sudo vim, put these two lines in your ~/.bashrc (or your shell's startup file):

export EDITOR=$(type -p vim)
export VISUAL=$(type -p vim)

Then you can sudoedit filename, which will:

1. Authenticate the user.
2. As root (UID 0), make a temporary copy of the file.
3. As $USER, use $VISUAL or $EDITOR to edit the temporary copy.
4. If the file was changed, as root, copy the temporary file back.

This will let you use your vim customizations, without worrying about imposing them on root.

Read man sudoedit.