Hi michaeldkfowler
You doesn't say part number. For example for LPC55s69, we can use shell demo

Running the demo
================
When the example runs successfully, the following message is displayed in the terminal:
~~~~~~~~~~~~~~~~~~~~~
SHELL (build: Jun 19 2020)
Copyright 2020 NXP
SHELL>> help
"help": Lists all the registered commands
"led arg1 arg2":
Usage:
arg1: 1|2|3|4... Led index
arg2: on|off Led status
"exit": Exit program
SHELL>> led 1 on
SHELL>> led 1 off
SHELL>> led 2 on
SHELL>> led 2 off
SHELL>> led 3 on
SHELL>> led 3 off
SHELL>> led 4 on
LED index is wrongs
SHELL>>
~~~~~~~~~~~~~~~~~~~~~
Note:
1,The shell information "SHELL (build: Jun 19 2020)" may be different, which depends on the compile date.
2,If the command 'led x on'/'led x off' run success, the corresponding LEDx on board will turn on/turn off.
But the valid "Led index" may be different, which depends how many LEDs are available on the specific board.
For example: one board only have LED1/LED2, then shell demo will print "LED index is wrong" for all led index bigger than 2.
Please have a try.
Thanks,
Jun Zhang