docs: update epics docs

docs/developer/python/epics.md

@@ -62,9 +62,34 @@ Type "help", "copyright", "credits" or "license" for more information.
 
 ## Systemd Services
 
-When ssh-ing into a machine, `/etc/profile.d/*` automatically gets sourced.
+When ssh-ing into a machine, `/etc/profile.d/*` automatically gets sourced. And thus we have:
+
+```
+[sls-vserv-bd-hla01-dev ~]$ env | grep EPICS
+EPICS_CA_ADDR_LIST=sls-cagw.psi.ch:5062
+```
 
 When running a `systemd` service, this does not happen.
 
+Note -- it seems that the following does not work as expected:
+```
 That's why we need to source `/etc/profile.d/cas_12_epics.sh` in our startup script
-to make sure that `EPICS` is configured properly.
+to make sure that `EPICS` is configured properly. 
+```
+After sourcing the script, we still have: `EPICS_CA_ADDR_LIST=` (i.e. the script does not set `EPICS_CA_ADDR_LIST=sls-cagw.psi.ch:5062`) in `systemd` service.
+
+Whereas in the shell `unset EPICS_CA_ADDR_LIST` and then `. /etc/profile/cas_12_epics.sh` properly sets `EPICS_CA_ADDR_LIST=sls-cagw.psi.ch:5062`.
+
+Check which env variables a `systemd` service is running with:
+
+```
+[sls-vserv-bd-hla01-dev ~]$ systemctl --user restart AGEBD-SERVICE-SCRUBBING.service && sleep 1 &&   PID=$(systemctl --user show -p MainPID --value AGEBD-SERVICE-SCRUBBING.service)
+[sls-vserv-bd-hla01-dev ~]$   tr '\0' '\n' < /proc/$PID/environ | grep EPICS
+EPICS_CAS_IGNORE_ADDR_LIST=
+EPICS_CA_ADDR_LIST= 129.129.146.255
+EPICS_HOST_ARCH=linux-x86_64
+EPICS_BASE_HOST_BIN=/opt/gfa/python-3.10/20220602/epics/bin/linux-x86_64
+PYEPICS_LIBCA=/opt/gfa/python-3.10/20220602/epics/lib/linux-x86_64/libca.so
+EPICS_BASE_VERSION=7.0.5.0
+EPICS_BASE=/opt/gfa/python-3.10/20220602/epics
+```