#!/bin/bash
# ======================================================================
# 
# flags: -s, use strong confirmation, only yes or YES or Yes is accepted
#
# Parameters:
# $@ - The confirmation message
#
# Examples:
# >  # Example 1
# >  # The preferred way to use confirm
# >  confirm Delete file1? && echo rm file1
# >   or 
# >   [[ confirm Delete file1 ]]; then
# >   rm file1 
# >   fi
# >
# >  # Example 2
# >  # Use the $? variable to examine confirm's return value
# >  confirm Delete file2?
# >  if [ $? -eq 0 ]
# >  then
# >      echo Another file deleted
# >  fi
# >
# >  # Example 3
# >  # Tell bash to exit right away if any command returns a non-zero code
# >  set -o errexit
# >  confirm Do you want to run the rest of the script?
# >  echo Here is the rest of the script
#
# ======================================================================

function confirm()
{
    local res="y Y yes YES Yes Sure sure SURE OK ok Ok"
    local strong="yes YES Yes" 
    [[ $1 =  "-s" ]] && { res=$strong; strong=true shift; } || strong="" 
    echo -n "$@" "$([[ $strong ]] && echo \< $res \>) ? "
    read -e answer
    for response in $res
    do
        if [ "_$answer" == "_$response" ]
        then
            return 0
        fi
    done

    # Any answer other than the list above is considered a "no" answer
    return 1
}