Clearing tmux terminal throws error: “'tmux-256color': unknown terminal type.”

Question

Originally, I was trying to determine why some directories show up differently colored than others when using the ls command.

While playing around with this. I have now encountered the problem of not being able to clear the screen inside a tmux terminal

$ clear
'tmux-256color': unknown terminal type.

This problem only persists in tmux, not the actual terminal itself and only showed up after trying to fix the initial problem. Also the colors have changed when running vim inside tmux now.

Here are some outputs:

outside tmux:

$ echo $TERM; tput colors; tput longname
xterm-256color
256
xterm with 256 colors

inside tmux:

echo $TERM; tput colors; tput longname
tmux-256color
tput: unknown terminal "tmux-256color"
tput: unknown terminal "tmux-256color"

EDIT:

my .bashrc file has:

case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

my .tmux.conf has:

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

Answer 1

Your plaform doesn't have tmux-256color, you will need to either:

1) Use screen-256color instead.

2) See if you can upgrade ncurses or terminfo to a later version with tmux-256color.

3) Copy tmux-256color from another computer which does have it, you can do this by saving it with infocmp -x tmux-256color >saved then installing it with tic -x saved.