Ask a Yes/No question and executes an action dependent on the answer

yesdo.sh

#!/bin/bash
#    Asks a user a Yes/No question and executes actions dependent on the answer.
#    Copyright (C) 2015 Christoph "criztovyl" Schulz
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

function yesdo()
# Ask the user a question and executes an action dependent on answer.
# Defaults to yes.
#
# Usage: question action notaction
#  question: the question asked ("[nY] " is appended)
#  action: executed on yes
#  notaction: executed on no.
{

    #Variables
    yes_lc="y"
    question=$1" [nY] "
    action=$2
    notaction=$3

    # Read single yes/no character
    read -n 1 -p "$question" char

    # Determine answer and executes action on yes (y or Y) or on nothing (newline)
    # Also determines if need to add a newline (if entered single character, not newline)
    nl="\n"; [ -z "$char" ] && nl="" || [ "${char,,}" == "y" ] && echo -ne "$nl" && eval "$action" || { echo -ne "$nl"; [ "$notaction" ] && eval "$notaction"; }
}