256 color support for vim background in tmux

Question

while using vim within tmux I can see that 256 color support is enabled. with $tput colors

However changing the colorscheme in vim while in tmux will change the colorscheme on a per line basis but not the entire background. see screenshot

Here is a snippet of the my .vimrc file for example. My original colorscheme is solarized dark and then after running :colorscheme molokai you see what happens.

info

• gnome-terminal
• bash

in my ~/.tmux.conf

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

in my ~/.vimrc

    set t_Co=256

in my ~/.bashrc

# ryan
export TERM="xterm-256color"
# ryan
alias tmux="tmux -2"

in my ~/.profile

# ryan 256 color support
if [ -e /usr/share/terminfo/x/xterm-256color ]; then
    export TERM='xterm-256color'
  else
    export TERM='xterm-color'
  fi

Any ideas how I can get a full colorscheme change in vim? Are all my snippets from the files looking good?

Answer 1

From the look of your .bashrc and .profile, the shells inside tmux are overriding the 'default-terminal' setting in your tmux conf. Something like this:

• tmux creates new shell with TERM=screen-256color
• .bashrc/.profile run, set TERM=xterm-256color
• vim runs, tries to use incorrect TERM for tmux

you can check this by running

echo $TERM

in a fresh tmux shell.

Tmux is relatively picky about having a terminal set correctly. If you can, set the term value in gnome-terminal's configuration, not in your .bashrc. Failing that, surround those settings with a check for "screen" or "screen-256color" TERM, and don't reset them in that case.

Tmux REALLY wants the terminal set to screen or screen-256color

Answer 2

As explained here, disable Background Color Erase (BCE) by clearing the t_ut terminal option (run :set t_ut= in Vim and then press Control+L to refresh the terminal's display) so that color schemes work properly when Vim is used inside tmux and GNU screen.

Answer 3

I've found a better way on this post. You can make an alias of tmux to tmux -2 which will force tmux to assume that the shell is using 256 color terminal.

Answer 4

This is what worked for me in #Ubuntu and #Mac:

# File: ~/.bashrc (Ubuntu), ~/.bash_profile (Mac)
# for VIM and TMUC
if [ "$TERM" = "xterm" ]; then
  export TERM=xterm-256color
fi
alias tmux='tmux -2'  # for 256color
alias tmux='tmux -u'  # to get rid of unicode rendering problem

Reload settings:

$ source ~/.bashrc # Ubuntu

$ source ~/.bash_profile # Mac

Set up .bashrc for Mac (as it is used by tmux)

# File: ~/.bashrc (Mac)
source ~/.bash_profile

Set up "default-terminal" option in ~/.tmux.conf.

# File: ~/.tmux.conf
set -g default-terminal "screen-256color"  # Mac and Ubuntu

Answer 5

I had very similar problem for gnome-terminal + tmux + vim but it was extended also to specific key combination problem: . I had to combine a few things together. first of all I had to setup my .tmux.conf into:

# Ensure terminal starts with its own colour scheme (helps Vim/Neovim themes to not break)
set -g default-terminal "xterm-256color"
# set -g default-terminal "screen-256color" # no S-Fx keys ;-(
# and ensure the key-codes are xterm alike
set -g xterm-keys on

Then in .vimrc:

if $COLORTERM == 'gnome-terminal'
      set t_Co=256
endif
set t_ut=

And that did the job for the keys and background.

Answer 6

If you still face issues: I noticed that vim falls back to using option t_Co=8 inside tmux even if $TERM is set to screen-256color. My workaround is this snippet in vimrc:

if exists("$TMUX")
        set t_Co=256
        set notermguicolors
else
        set termguicolors
endif

The $TMUX variable is only filled if inside a tmux session. In this case, I allow vim to use 256 colors. Note that I also unset termguicolors as tmux does not support true colors.

Answer 7

A quick fix is to run the following in the terminal.

export TERM=xterm-color

You could add it to your ~/.bash_profile or other profile to always be set on start.

Answer 8

Just now faced the same problem. Based on bloy's answer and current content of my ~/.profile (actually, it's the same as winchendonsprings') I've solved my problem as follows:

~/.profile:

if [[ -z $TMUX ]]; then
    if [ -e /usr/share/terminfo/x/xterm+256color ]; then # may be xterm-256 depending on your distro
        export TERM='xterm-256color'
    else
        export TERM='xterm'
    fi
else
    if [ -e /usr/share/terminfo/s/screen-256color ]; then
        export TERM='screen-256color'
    else
        export TERM='screen'
    fi
fi

Logic is simple: if we're not inside tmux session, then use xterm (colored or not). Otherwise the same thing for screen.

Maybe it's too verbose, but you got the idea.