This is problem:
if [[$variable == $blanko]];
Spaces are required inside square brackets, use it like this:
[[ "$variable" == "$blanko" ]] && echo "Nichts da!" || echo "$variable"
This is problem:
if [[$variable == $blanko]];
Spaces are required inside square brackets, use it like this:
[[ "$variable" == "$blanko" ]] && echo "Nichts da!" || echo "$variable"