Question

Is there a config entry I can place in my .vimrc which will achieve the same as passing the -X flag when running vim.

To provide some context:
I recently found that my vim startup time in a screen (tmux) session was extremely long (~6 seconds)

Using the vim --startuptime flag, it is clear that the issue is due to the connection to the X server in order to setup the X clipboard.

Running vim -X has fixed my slow startup time. I would prefer to modify my .vimrc, rather than creating a bash alias to solve this.

Answer 1

You may want to take a look at the clipboard setting (:help 'clipboard'). What follows is a recommendation from Gary Johnson (source, via web.archive.org).

---

You may want to set ‘clipboard’ in your .vimrc so that you don’t
have to use -X all the time. In my situation, I use vim on a
machine that I log in to from various other machines, some of which
have $DISPLAY set even though they don’t have an X server. Here is
what I have in my .vimrc:

" Prevent vim from trying to connect to the X server when connecting 
" from home, which causes a startup delay of about 14 seconds. I 
" usually connect from home via screen. 
" 
"set clipboard=autoselect,exclude:cons\\\|linux\\\|screen 
" 
" Using $DISPLAY instead of 'term' should be more reliable. It avoids 
" the problem of starting vim without first starting screen and allows 
" screen to be used locally without losing vim's X features. 
" 
if $DISPLAY =~ '\(\(cos\|scs\)\d\+nai\d\+\)\|\(spkpc\d\+\)\|\(tc-garyjohn\)' 
set clipboard=autoselect,exclude:.* 
endif 

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(Do notice that you’ll need to tweak the if $DISPLAY line to match your own $DISPLAY variable).