tmux

Attach to last session	tmux a

Ctrl + b to enter command, one of the following:

set setting	`:`, then type
enable mouse support	`set -g mouse on`

if [ -z "$TMUX" ] && [ -n "$SSH_TTY" ]; then
    tmux attach-session -t ssh || tmux new-session -s ssh
    exit
fi

Your system doesn't have xterm-256color. You could:

export TERM=xterm

Maybe the file /usr/share/terminfo/x/xterm-256color is corrupted. It may be fixed upon (system/package) upgrade / reinstall.

Meanwhile you can use other terminfo entry. You can get the available options by ls /usr/share/terminfo/x.

ln -sf /usr/share/terminfo/x/xterm-color /usr/share/terminfo/x/xterm-256color

Commands