intermediate
Bash Variable Expansion Edge Cases
Explain nuances of unset versus empty string variables in Bash scripting.
📝 Nội dung Prompt
Explain the behavioral difference in Bash between testing if a variable is unset versus testing if it is set to an empty string "". Provide a script snippet demonstrating the difference between using -z, -n, and ${var:-default} expansions when the variable holds the value "".