power off/on ioc recovery

["Tran, Phi Dung via Tech-talk" <tech-talk@aps.anl.gov>]

Hello,

  I'm trying to run a Python script from within my IOC startup script (st.cmd) to auto-generate a configuration file before iocInit(). However, I'm finding that the system() command is not available in my EPICS build.

  Background - Motor Position Restoration Problem:

  I need to restore motor positions after a Galil motor controller power cycle. I discovered that:

  - Pass0 restore alone works when only restarting the IOC (controller stays powered on)

  - Pass0 restore fails when the controller is power cycled - the controller resets to 0, and motor record initialization overwrites the restored VAL field with the controller's position (0)

  My Solution:

  I use SET mode after iocInit() to restore positions without motor movement. To avoid hardcoded values, I wrote a Python script (generate_restore.py) that reads the latest autosave file and generates the restoration script with

  current saved values.

  What I'm trying to do:

  Run this Python script automatically during IOC startup (before iocInit) to ensure the restoration script always has the latest saved positions.

  What I've tried:

  system("cd /path/to/script && /usr/bin/python3 generate_restore.py")

  Error received:

  st.cmd line X: Command system not found.

  Also tried:

  - shell "command" - Command not found

  - ! command - Command not found

  - iocshCmd and iocshRun - Only execute EPICS commands, not shell commands

  Environment:

  - EPICS Base: R7.0.5

  - OS: Red Hat Enterprise Linux 8.10

  - IOC built from Galil motor driver (Galil-3-0/3-6)

  Questions:

  1. Is there a way to execute shell commands from within st.cmd in EPICS 7.0.5?

  2. Is system() command availability dependent on build configuration or compile-time options?

  3. Are there alternative approaches to run external scripts during IOC initialization?

  4. Is there a better approach to handle motor position restoration after controller power cycle?

  Current workaround:

  Running python3 generate_restore.py && ./st.cmd manually before each IOC start, but I'd prefer an automated solution.

  Any suggestions would be greatly appreciated!

  Thanks,

Alex