=====Identify Automatically Started System Processes=====


====Systemd====
Replaces the older and clunkier init. Default as of RH7. Manages various things

^  Services  | Daemons |
^  Path   | watches files |
^  Mount  | controls mounts |
^  Timer  | scheduling  |
^  Slice  | resource management |
^  socket  | listens to ports |
^  target   | groups units |

YOu can see the processes using **pstree -p **

Systemd divives your system into manageable chunks to see them 
<code> systemcctl list-units </code>

You can specify to just list a particular type
<code> systemctl list-units -t services -a </code>
the -a will showe all se3rvices including those not active or installed that systemd knows about

You can also check if a service is enabled and or activbe with 
<code> systemctl is-active service name</code>

If a service is not enabled you can enable it and start it with one command
<code> systemctl enable --now service-name</code>

List the enabled or disabled states of all service units.
<code> systemctl list-unit-files --type=service </code>

====working with services====
Every service has a process ID you can see it using systemctl or you can try using 
<code> pidof service</code> this will show you all the process ids associated with that service. Ussually the lowest one is the main one and others are branches.

===reload===
you can reload a service to cause it to reread the configuration file. This does not affect the PID ofr aq service those stay the same
===restart=== 
this restarts the service and it gets a new PID

if you are unsure if you can reload a service you can try the 
<code> systemctl reload-or-restarrt service </code>  first tries a reload if tht does not work it will relstart it

ypu can also list the dependencies of a service

<code> systemctl list-dependencies service </code>  you can also see what calls the service with the <code>--reverse </code> option

The system can also mask a service so it will not run even to satisfy a dependency
<code> systemctl mask service </code>