bash function to determine the boot type (on RHEL systems)

function fn_get_boot_type()
{
  #--- Determine the boot type (UEFI or BIOS). This is used for manifest automation
  LOG_MSG="Checking for boot type"
  fn_write_to_log
  BOOT_TYPE=$([ -d /sys/firmware/efi ] && echo UEFI || echo BIOS)
  LOG_MSG="Boot Type: ${BOOT_TYPE}"
  fn_write_to_log
}