mc unknown terminal tmux

bash-4.2$ mc

Unknown terminal: screen.xterm-256colorCheck the TERM environment variable. Also make sure that the terminal is defined in the terminfo database. Alternatively, set the TERMCAP environment variable to the desired termcap entry.

Решение: 

bash-4.2$ export TERM=xterm

Также можно добавить export TERM=xterm в .profile если есть права.