debian-bash/lib/functions.sh

##
# return 0 (true) if array (passed by name) contains element 
# usage: 
#   ARRAY = ( a b c )
#   containsElement ARRAY 'a' => 0
containsElement () {
	local -a 'arraykeys=("${!'"$1"'[@]}")'
  if $(isArray $1); then
	  for index in ${arraykeys[*]}; do 
  		current=$1"[$index]"
		  [[ "${!current}" == "$2" ]] && return 0; # found
	  done
	  return 1; # not found
  else
    >&2 echo "ERROR: $1 not an array!" 
    return 2; # not an array
  fi
}

isArray(){
  [[ "$(declare -p $1 2> /dev/null)" =~ "declare -a" ]] && return 0; # is an array
  return 1; # not an array
}

##
# 
askConfirmation () {
  case "$1" in
    y|Y|yes|YES ) 
      QUESTION="(Y/n)?"
      DEFAULT=0
      ;;
    * ) 
      QUESTION="(y/N)?"
      DEFAULT=1
      ;;
  esac
  read -p "$QUESTION : " choice
  case "$choice" in 
    y|Y|yes|YES ) return 0;; #true
    n|no|N|NO ) return 1;; #false
    * ) return $DEFAULT;;
  esac  
}