#${1:-text} gives text when the argument is not given or empty
sayGoodbye() {
local message=${1:-"Goodbye!"}
local times=${2:-1}
local i
for ((i = 0; i < times; i++)); do
echo "$message"
done
}
sayGoodbye
#prints "Goodbye!"
sayGoodbye "see you"
#prints "see you"
sayGoodbye "bye" 2
#prints "bye" twice
#the arguments have no names: "" skips the first one
sayGoodbye "" 2
#prints "Goodbye!" twice