Interview › Scripting (Bash, Groovy)
What are string test operators (-z, -n) used for? [Basic]
Answer
-z checks whether a string is empty, and -n checks whether a string is non-empty. I use them to validate optional and required inputs.
Technical explanation
Quote variables with [ ] to avoid syntax errors when values are empty or contain spaces.
With [[ ]], empty variables are safer, but quoting still improves clarity.
For required environment variables, ${var:?message} is often even cleaner.
Hands-on example
name="${1:-}"
if [[ -z "$name" ]]; then
echo "name is required" >&2
exit 2
fi
[[ -n "${DEBUG:-}" ]] && echo "debug enabled
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