Multiple choice technology

What does it mean ${parameter:-5}

  1. If parameter exists and isn't null, return its value; otherwise return 5

  2. If parameter exists and isn't null, return its value; otherwise set it to 5 and then return it

  3. If parameter exists and isn't null, return 5; otherwise return null.

  4. None of the above
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A Correct answer
Explanation

${parameter:-word} is parameter expansion that returns 'word' if parameter is unset or null, but doesn't assign it. This differs from ${parameter:=word} which would assign the value. Option A correctly describes this default value behavior.

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