256 color

• tmux

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

• bash, zsh

export TERM=screen-256color
export TERM=xterm-256color

• screen

term screen-256color

• putty

1. Settings -> Windows -> Colours -> "Allow terminal to use xterm 256-colour mode"
2. Settings -> Connection -> Data -> Terminal-type string to "xterm-256color".