show only username if fullname not provided

mantablockscreen

@@ -5,6 +5,11 @@ cachepath=$HOME/.cache/mantablockscreen
 cropuser=$cachepath/$USER-pic-crop.png
 fullname=`getent passwd $USER | cut -d ":" -f 5`
 full_alias="${fullname} (${USER})"
+if [[ -n $fullname ]]; then
+	full_alias="${fullname} (${USER})"
+else
+	full_alias=$USER
+fi
 
 width=$(xrandr --query | grep ' connected' | grep -o '[0-9][0-9]*x[0-9][0-9]*[^ ]*' | sed -r 's/^[^0-9]*([0-9]+x[0-9]+).*$/\1/' |cut -d "x" -f 1)
 height=$(xrandr --query | grep ' connected' | grep -o '[0-9][0-9]*x[0-9][0-9]*[^ ]*' | sed -r 's/^[^0-9]*([0-9]+x[0-9]+).*$/\1/' |cut -d "x" -f 2)