[Closes #1] Add a simple, non-configurable confirm script
[Closes #1] Add a simple, non-configurable confirm script

As short as this script is, its behavior is already quite subtle.
Breaking down the code, we have:

    read -p "Confirm? [Y/n] " response

The `read` built-in prints the prompt given by `-p` and collects one
line of input into a shell variable `response`.  It automatically
trims any leading and trailing whitespace.

    [[ -z "$response" || "${response,,}" = y* ]]

Keyword `[[` (as opposed to the command `[`) allows us to match
against the pattern `y*`, which accepts any input starting with 'y'.
Parameter expansion `${response,,}` converts input to lower case, and
test `-z` checks for zero-length input (i.e. just pressing enter).

rriegs/confirm