SC2105

break is only valid in loops

Problematic code:

case "$1" in
    -v)
       verbose=1
       break
       ;;
    -d)
       debug=1
esac

Correct code:

case "$1" in
    -v)
       verbose=1
       ;;
    -d)
       debug=1
esac

Rationale:

break or continue was found outside a loop. These statements are valid only in loops. In particular, break is not required in case statements as there is no implicit fall-through.

To return from a function or sourced script, use return. To exit a script, use exit.

Exceptions:

It's possible to break/continue in a function without a loop. The call will then affect the loop – if any – that the function is invoked from, but this is obviously not good coding practice.