Strange behavior of vim color inside screen with 256 colors

I was trying to make the syntax highlighting (with 256 colors) of vim work inside screen, which is running inside gterm.

vim

screen

gterm

It works quite fine in the beginning. What I mean by "in the beginning" is, after I start screen, and enter vim, the colors look fine, and there are really 256 colors.

screen

vim

But after a while (I don't know exactly how long) the colors automatically change back to an appearance as if there are only 8 (or 16?) colors.

For example, after this has already occurred, if I enter the command

hi Comment ctermfg=68


inside vim, the comments appear to be "pure" green; however, if I open another vim outside screen (in the same terminal), then with the same command the comments appear to be a "yellowish" green.

vim

vim

The following is my .screenrc settings related to color:

attrcolor b ".I"
defbce "on"
termcapinfo xterm 'Co#256:AB=E[48;5;%dm:AF=E[38;5;%dm'
term xterm-256color


After running a python script to display all the colors, I find out that maybe this is a problem of screen itself, and has nothing to do with vim.

What I did is, inside the screen session with problems, this script gives 256 colors, but many of them are actually the same; however, when I start a new screen session with the same configuration, this script gives 256 colors which are distinct from each other.

screen

Edit:

Last night I connected to my Linux computer (which is in my office and it is always on) with putty, then opened a screen session with multiple windows in it. The colors are correct last night. Then before I went to sleep I detached the screen session and closed putty.

putty

screen

screen

putty

Now in the morning when I attach that screen session in putty again, the colors crash: they appear as if there are only 8 colors.

screen

putty

The colors are fine outside screen (but still in putty).

screen

putty

Edit:

Three years later after I asked this question, today I saw a similar problem. The problem is that vim can display 256 colors outside screen, and screen can display 256 colors with a test script, but vim can't display any color (can only display black and white) inside screen. Just as a note to myself, here is the .screenrc file I am using

vim

screen

screen

vim

screen

.screenrc

hardstatus alwayslastline "%{.bW}%-w%{.rW}%n %t%{-}%+w %=%{..G} %H %{..Y} %Y-%m-%d %c"
shell "bash"
startup_message off
vbell off
altscreen on
attrcolor b ".I"
defbce "on"
termcapinfo xterm* 'is=E[rE[mE[2JE[HE[?7hE[?1;4;6l'
termcapinfo xterm 'Co#256:AB=E[48;5;%dm:AF=E[38;5;%dm'
term screen-256color


The solution to the problem is already mentioned in the accepted answer, namely, I need to include

export TERM=xterm-256color


in .bashrc.

.bashrc

term xterm-256color

screen-256color

termcapinfo

TERM

xterm-256color

2 Answers
2

Set TERM to xterm-256color in your .bashrc, and put term screen-256color in your .screenrc.

TERM

xterm-256color

.bashrc

term screen-256color

.screenrc

Here's why this breaks: gnome-terminal, screen, tmux, bash, putty and vim have all been written to intelligently handle 256 colors, but you need to set things up correctly at the earliest possible point. Using termcapinfo in your .screenrc is actually a duct tape solution!

termcapinfo

.screenrc

If your TERM is set correctly, it will signal to bash that you're in 256-color mode, which means it will play nice with screen being in 256-color mode as well.

TERM

So, in your .bashrc, export TERM=xterm-256color. [1]

.bashrc

export TERM=xterm-256color

In your .screenrc, use screen-256color for TERM instead of xterm-256color, and delete the rest of the cruft!

.screenrc

screen-256color

TERM

xterm-256color

In your PuTTy configuration, use putty-256color.

putty-256color

You can download the termcap entry files and put them in ~/.terminfo/s and ~/.terminfo/p, if your box doesn't have them by default.

~/.terminfo/s

~/.terminfo/p

Footnotes

[1] Setting TERM to xterm-256color in your .bashrc can be a little presumptuous, especially if you use the same .bashrc on multiple machines. I have found the following snippet to be fairly effective:

TERM

xterm-256color

.bashrc

.bashrc

case "$TERM" in
*-256color)
alias ssh='TERM=${TERM%-256color} ssh'
;;
*)
POTENTIAL_TERM=${TERM}-256color
POTENTIAL_TERMINFO=${TERM:0:1}/$POTENTIAL_TERM

# better to check $(toe -a | awk '{print $1}') maybe?
BOX_TERMINFO_DIR=/usr/share/terminfo
[[ -f $BOX_TERMINFO_DIR/$POTENTIAL_TERMINFO ]] &&
export TERM=$POTENTIAL_TERM

HOME_TERMINFO_DIR=$HOME/.terminfo
[[ -f $HOME_TERMINFO_DIR/$POTENTIAL_TERMINFO ]] &&
export TERM=$POTENTIAL_TERM
;;
esac


The alias of ssh is a defensive measure to prevent us from trying to open a 256-color terminal on a remote machine that doesn't necessarily support it. The main block is the other half of the equation; it checks to see if the corresponding terminfo entry exists, and sets it if it does.

alias

Max has an excellent answer, but I actually had to reinstall screen with ./configure --enable-colors256 to ensure that the config.h file had #define COLORS256 1 set, which was not the case by default on my machine. Then, I found that the other settings were not necessary so long as I ensured that my TERM was set to xterm-256color.

./configure --enable-colors256

config.h

#define COLORS256 1

TERM

xterm-256color

screen

brew install screen

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