rc/sh/confirm

#!/usr/bin/env bash
if [ -n "${ZSH_VERSION:-}" ]; then
    confirm() {
        read -q '?Continue? [y/N] '
        ret=$?
        echo
        return $ret
    }
else
    confirm() {
        # specify stdin (1) to avoid taking input from pipes
        read -n1 -u 1 -p "Continue? [y/N] " c
        echo
        [ "$c" != 'y' ] && [ "$c" != 'Y' ] && return 1
        return 0
    }
fi
confirm