Multiple choice technology operating systems

$ i=1 $ j=A $ A1=hello These 3 variables are defined. Which of the following commands will display hello?

  1. eval echo ${j}${i}
  2. eval echo $${j}${i}
  3. eval echo \$${j}${i}

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The eval command performs two levels of variable expansion. First, ${j}${i} expands to 'A1'. Then \$ becomes a literal $, so the final command becomes '$A1', which evaluates to the value of the A1 variable ('hello'). Option C correctly constructs this two-stage expansion with proper escaping.

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