What does the code 'while :; do echo hi; done' do?

• A. It prints hi then exits
• B. It runs a fixed number of times
• C. It loops indefinitely printing hi
• D. It prints nothing

Answer: (C)

In shell scripting, : is a built-in no-op that always returns a successful status. The while loop continues as long as the condition is true, and since : always evaluates to true, the loop never ends. The body prints hi each time, so you get an endless stream of hi until you stop the process. This matches the idea of looping indefinitely while printing hi. It doesn’t exit after a single print, it doesn’t print nothing, and it isn’t limited to a fixed number of iterations.