Validate if tmux exists and send the buffer to an empty stream /dev/null
-> which tmux 2>&1 >/dev/null
If session hack
exists it recover it -> tmux attach -t hack
Otherwise, It create a new session call hack
-> tmux new -s hack
if which tmux 2>&1 >/dev/null; then
if [ $TERM != "screen-256color" ] && [ $TERM != "screen" ]; then
tmux attach -t hack || tmux new -s hack; exit
fi
fi