Interview › Scripting (Bash, Groovy)
How do you check whether a command exists before using it? [Intermediate]
Answer
I check whether a command exists with command -v name >/dev/null 2>&1. It is portable and avoids relying on which, which may be external and inconsistent.
Technical explanation
Validate dependencies at script startup so failures are clear and early.
Use a loop for multiple required tools and print installation guidance if helpful.
For optional tools, use command -v to choose a fallback path.
Hands-on example
require() {
command -v "$1" >/dev/null 2>&1 || {
echo "required command not found: $1" >&2
exit 127
}
}
for cmd in kubectl jq curl; do
require "$cmd"
done
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