I show the hard-disk free space in hardstatus screen. But also I want change the color of this value when it's less than a value to alert me.I have done a script that it checks this and it returns a string if it's true or nothing if it's false.But the problem is change the color in hardstatus screen. This is the line:   hardstatus alwayslastline %?%27`%{+B r}%?VelocidadThe hardstatus works but I won't show the output of script check (%27), only change the color. But %? needs a not empty string to do this. How can I do this?
Change screen hardstatus color dynamically 
linux;scripting;configuration;gnu screen