Status display for all robot services

[dannystaple]

While debugging with @dblanding, it has become clear that a failing service on the robot will issue stop/all, but may lead to other problems.
There are multiple services, and while running journalctl on each will show something, a display for all statuses.

[dannystaple]

I think I've got something, which requires a handy appendix B command, but not changing the code:

danny@learnrob3-2:~ $ systemctl list-units --all --no-pager $(systemctl show -p Before mosquitto.service --value)
  UNIT                            LOAD   ACTIVE   SUB     DESCRIPTION                                
  config_store.service            loaded active   running config_store
  distance_sensor_service.service loaded active   running distance_sensor_service
  inventor_hat_service.service    loaded active   running inventor_hat_service
  launcher_service.service        loaded active   running launcher_service
● voice_agent.service             loaded failed   failed  voice_agent
  web_server.service              loaded active   running web_server
  wheel_control_service.service   loaded active   running wheel_control_service                      
  multi-user.target               loaded active   active  Multi-User System
  shutdown.target                 loaded inactive dead    System Shutdown

Legend: LOAD   → Reflects whether the unit definition was properly loaded.
        ACTIVE → The high-level unit activation state, i.e. generalization of SUB.
        SUB    → The low-level unit activation state, values depend on unit type.

10 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.

It's even got color annotations:

[dannystaple]

Got an even tidier version:

danny@learnrob3-2:~ $ systemctl list-units --all --no-pager $(systemctl show -p Before mosquitto.service --value) --type=service
  UNIT                            LOAD   ACTIVE SUB     DESCRIPTION            
  config_store.service            loaded active running config_store
  distance_sensor_service.service loaded active running distance_sensor_service
  inventor_hat_service.service    loaded active running inventor_hat_service
  launcher_service.service        loaded active running launcher_service
● voice_agent.service             loaded failed failed  voice_agent
  web_server.service              loaded active running web_server
  wheel_control_service.service   loaded active running wheel_control_service

Legend: LOAD   → Reflects whether the unit definition was properly loaded.
        ACTIVE → The high-level unit activation state, i.e. generalization of SUB.
        SUB    → The low-level unit activation state, values depend on unit type.

7 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.

[dblanding]

Nice!

…

On Wed, Dec 3, 2025 at 7:30 AM Danny Staple ***@***.***> wrote: *dannystaple* left a comment (PacktPublishing/Learn-Robotics-Programming-3rd-edition#32) <#32 (comment)> Got an even tidier version: ***@***.***:~ $ systemctl list-units --all --no-pager $(systemctl show -p Before mosquitto.service --value) --type=service UNIT LOAD ACTIVE SUB DESCRIPTION config_store.service loaded active running config_store distance_sensor_service.service loaded active running distance_sensor_service inventor_hat_service.service loaded active running inventor_hat_service launcher_service.service loaded active running launcher_service ● voice_agent.service loaded failed failed voice_agent web_server.service loaded active running web_server wheel_control_service.service loaded active running wheel_control_service Legend: LOAD → Reflects whether the unit definition was properly loaded. ACTIVE → The high-level unit activation state, i.e. generalization of SUB. SUB → The low-level unit activation state, values depend on unit type. 7 loaded units listed. To show all installed unit files use 'systemctl list-unit-files'. — Reply to this email directly, view it on GitHub <#32 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AMXQDUGVHTZ4OL4Y56DCO7L373JURAVCNFSM6AAAAACN2Z7F46VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTMMBWGYZTIMJQHE> . You are receiving this because you were mentioned.Message ID: <PacktPublishing/Learn-Robotics-Programming-3rd-edition/issues/32/3606634109 @github.com>

[dannystaple]

Appendix B has been submitted with this added.

[dannystaple]

I think we want to reference this part of Appendix B in an earlier chapter, to make it part of reader debugging practices, as it may give a quick diagnosis of many issues. Reopening to insert in the next chapter I'm editing - likely chapter 12.