Split a string simple bash function

split-string.sh

#!/bin/bash

# Split a string returning the specified index (or 2nd instance by default)

if [ -z "$1" ] || [ -z "$2" ]; then
    echo "Provide split delimiter and string"
else
    delim="$1"
    string="$2"
    if [ -z "$3" ]; then
        split_index=2
    else
        split_index="$3"
    fi
    echo "$2" | cut -d$1 -f $split_index
fi