VIM

Create the /etc/vim/vimrc.local:

vi /etc/vim/vimrc.local

" Prevent the defaults from being loaded again later, if the user doesn't                                                                                                                     
" have a local vimrc (~/.vimrc)                                                                                                                                                               
let skip_defaults_vim = 1                                                                                                                                                                     

" Set more options (overwrites settings from /usr/share/vim/vim80/defaults.vim)                                                                                                               
" Add as many options as you wish                                                                                                                                                             
" Set the mouse mode to 'r'                                                                                                                                                                   
if has('mouse')                                                                                                                                                                               
 set mouse=r                                                                                                                                                                                  
endif                                                                                                                                                                                         

" Toggle paste/nopaste automatically when copy/paste with right click in insert mode:                                                                                                         
let &t_SI .= "\<Esc>[?2004h"                                                                                                                                                                  
let &t_EI .= "\<Esc>[?2004l"                                                                                                                                                                  

inoremap <special> <expr> <Esc>[200~ XTermPasteBegin()                                                                                                                                        

function! XTermPasteBegin()                                                                                                                                                                   
 set pastetoggle=<Esc>[201~                                                                                                                                                                   
 set paste                                                                                                                                                                                    
 return ""                                                                                                                                                                                    
endfunction  

Commands:

Add string to the beginning of each line:

:%s/^/string/

Add string to the end of each line:

:%s/$/\string/g

Delete all text:

:%d