Multiple choice technology operating systems

Which of the following is not a shell program control structure?

  1. while-do-done

  2. until-do-done

  3. repeat-do-done

  4. if-then-fi

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Standard shell programming provides while-do-done, until-do-done, if-then-fi, for-do-done, case-esac, and select-do-done control structures. There is no 'repeat-do-done' construct in bash/sh/ksh - this is invalid shell syntax, making option C the correct answer as the non-existent structure.