No syntax highlighting in tmux

Question

I installed tmux in iTerm 2.(Build 3.0.13) When I execute vim in tmux, syntax highlighting looks like this.

But outside tmux, syntax highlighting looks fine.

My $TERM inside and outside tmux is xterm-256color. I also added

set -g default-terminal "screen-256color"

in .tmux.conf and added this

set t_Co=256
set t_AB=m
set t_AF=m
if &term =~ '256color'
    set t_ut=
endif

in .vimrc.

I also tried tmux -2 command and read these questions.

lose vim colorscheme in tmux mode

Incorrect colors with vim in iTerm2 using Solarized

Is this a problem of tmux, vim, or my configuration?

EDIT:

My .vimrc in GitHub Gist

https://gist.github.com/sohnryang/3c63397f332f2e30c7d7b2a83c3c9f52

What will happen when you start your tmux with -2 option: tmux -2. Preferably when there are no sessions in tmux. — grodzik, Dec 22 '16 at 14:17
Running on tmux in iTerm 3.0.12, setting termguicolors instantly changes my syntax highlighting to black and white (but still highlights, if only in bold). — muru, Dec 24 '16 at 13:13
@muru, I added set termguicolors in .vimrc, everything is same. — sohnryang, Dec 25 '16 at 02:41
@sohnryang that's what I'm saying, maybe you shouldn't. You have it set right before you call pathogen. — muru, Dec 25 '16 at 03:46
What's the difference between setting termguicolors before calling pathogen and after calling pathogen? — sohnryang, Dec 26 '16 at 09:03
@muru Anyway, I set termguicolors after pathogen, but problem persists. — sohnryang, Dec 26 '16 at 10:02
@sohnryang what part of "maybe you shouldn't" do you not understand? — muru, Dec 26 '16 at 10:02
Try following these steps. You have a whole lot of plugins so perhaps one of those is interfering. — Martin Tournoij, Dec 31 '16 at 03:49

score 15 · Accepted Answer · edited Apr 13 '17 at 12:51

15

Well, I solved the problem by myself.

as @Carpetsmoker♦ commented, I started to suspect that my .vimrc is a problem. I read this question and started vim with this command inside tmux.

vim -u NONE -U NONE -N ~/.vimrc

After starting vim with command above, I ran this command inside vim.

:syn on
:colorscheme solarized8_dark

These highlighted my .vimrc file. So, I started to debug my .vimrc.

Long story short, set termguicolors was the problem. If I ran vim with set termguicolors commented in .vimrc, I could see corrected syntax highlighting in tmux.

edited Apr 13 '17 at 12:51

Community

1

answered Jan 22 '17 at 01:49

sohnryang

495
1
3
14

I had the same issue. would be great to get termguicolors working on tmux though – filype Jan 26 '17 at 11:29
thank you! this fixed it, I spent quite a while trying to figure this out – Jackson Holiday Wheeler Mar 18 '21 at 21:27

ixil · Answer 2 · 2021-05-29T16:40:47.413

9

From the vim manual: :h termguicolors recommends reading :h xterm-true-color, also see :h $TERM

Sometimes setting 'termguicolors' is not enough and one has to set the |t_8f|
and |t_8b| options explicitly.  [ ... these are]  only set [to some default] when `$TERM` is `xterm`.

I use a condition similar to the below: (nvim recommends not using &term but rather $TERM )

if $TERM =~# '256color' && ( $TERM =~# '^screen'  || $TERM =~# '^tmux' )
    let &t_8f = "\<Esc>[38;2;%lu;%lu;%lum"
    let &t_8b = "\<Esc>[48;2;%lu;%lu;%lum"
    set termguicolors
endif

edited May 29 '21 at 16:40

answered Jun 11 '19 at 12:15

ixil

146
1
2

This one worked for me on NVim. Running on Arch and Fish shell – olleh Apr 29 '20 at 10:27

score 5 · Answer 3 · answered Apr 30 '18 at 04:54

5

I actually made it work just fine with termguicolors. This is what I did 1. in my ~/.bash_profile i put this:

export TERM=xterm-256color

and inside my ~/.vimrc I had this

syntax enable
colorscheme Spacegray

set termguicolors

and it worked perfectly! reference

answered Apr 30 '18 at 04:54

abbood

733
9
23

:syn on : colorscheme Spacegray : set termguicolors – abbood May 09 '18 at 15:33
In my case, it worked well without set termguicolors. Thank you, anyway! – GyuHyeon Choi Apr 19 '20 at 05:24
Adding the export fixed it in my case, nice work! – Jackson Holiday Wheeler Mar 18 '21 at 21:29

No syntax highlighting in tmux

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