Create relative symlinks files - use the relative path from the desired output directory to the storage path
    e.g. ../../2013-SEQ-0072/simulated/40/50_150/simulated_trimmed/2013-SEQ-0072_simulated_40_50_150_R1.fastq.gz
    is the relative path to the output_dir. The link name is the base name of the source file joined to the desired
    output directory e.g. output_dir/2013-SEQ-0072/2013-SEQ-0072_simulated_40_50_150_R1.fastq.gz
    https://stackoverflow.com/questions/9793631/creating-a-relative-symlink-in-python-without-using-os-chdir
    :param src_file: Source file to be symbolically linked
    :param output_dir: Destination folder for the link
    :param output_name: Optionally allow for the link to have a different name
    :param export_output: type BOOL: Optionally return the absolute path of the new, linked file
    :return output_file: type STR: Absolute path of the newly-created symlink

def relative_symlink(src_file, output_dir, output_name=None, export_output=False):
    """
    Create relative symlinks files - use the relative path from the desired output directory to the storage path
    e.g. ../../2013-SEQ-0072/simulated/40/50_150/simulated_trimmed/2013-SEQ-0072_simulated_40_50_150_R1.fastq.gz
    is the relative path to the output_dir. The link name is the base name of the source file joined to the desired
    output directory e.g. output_dir/2013-SEQ-0072/2013-SEQ-0072_simulated_40_50_150_R1.fastq.gz
    https://stackoverflow.com/questions/9793631/creating-a-relative-symlink-in-python-without-using-os-chdir
    :param src_file: Source file to be symbolically linked
    :param output_dir: Destination folder for the link
    :param output_name: Optionally allow for the link to have a different name
    :param export_output: type BOOL: Optionally return the absolute path of the new, linked file
    :return output_file: type STR: Absolute path of the newly-created symlink
    """
    if output_name:
        file_name = output_name
    else:
        file_name = os.path.basename(src_file)
    #
    output_file = os.path.join(output_dir, file_name)
    try:
        os.symlink(
            os.path.relpath(
                src_file,
                output_dir),
            output_file
        )
    # Ignore FileExistsErrors
    except FileExistsError:
        pass
    # Return the absolute path of the symlink if requested
    if export_output:
        return output_file