Bash helper tools to find a defined and/or non empty variable from a list of variable names

bash-find-defined-or-non-empty.sh

val1=""
val2="asd"

function firstDefinedName() {
	for varName in "$@"; do
		if [[ ! -z "${!varName+____}" ]]; then 
			echo "$varName"
			break
		fi
	done
}

echo "\""$(firstDefinedName val0 val1 val2)"\"" "== val1"


function firstDefinedValue() {
	for varName in "$@"; do
		if [[ ! -z "${!varName+____}" ]]; then 
			echo "${!varName}"
			break
		fi
	done
}

echo "\""$(firstDefinedValue val0 val1 val2)"\"" "== empty string"

function firstNonEmptyName() {
	for varName in "$@"; do
		if [[ -n "${!varName}" ]]; then 
			echo "$varName"
			break
		fi
	done
}

echo "\""$(firstNonEmptyName val0 val1 val2)"\"" "== val2"


function firstNonEmptyValue() {
	for varName in "$@"; do
		if [[ -n "${!varName}" ]]; then
			echo "${!varName}"
			break
		fi
	done
}

echo "\""$(firstNonEmptyValue val0 val1 val2)"\"" "== asd"

function one() {
	local val1="qwe"
	echo "inside function local space with 'local val1=\"qwe\"'"
	echo "\""$(firstNonEmptyValue val0 val1 val2)"\"" "== qwe"
}
one