openrc, rc-status, rc-service, rc-update: add pages (#3800)

* rc-status: add page

* openrc: add page

* rc-service: add page

* rc-update: add page

* rc-status: add list all runlevels example

* openrc: fix travis errors

* rc-status: fix travis errors again

* Update pages/linux/rc-update.md

Co-Authored-By: Zlatan Vasović <zlatanvasovic@gmail.com>

* Update pages/linux/rc-status.md

Co-Authored-By: Zlatan Vasović <zlatanvasovic@gmail.com>

Co-authored-by: Zlatan Vasović <zlatanvasovic@gmail.com>

pages/linux/rc-service.md

@@ -0,0 +1,32 @@
+# rc-service
+
+> Locate and run OpenRC services with arguments.
+> See also `openrc`.
+
+- Show a service's status:
+
+`rc-service {{service_name}} status`
+
+- Start a service:
+
+`sudo rc-service {{service_name}} start`
+
+- Stop a service:
+
+`sudo rc-servie {{service_name}} stop`
+
+- Restart a service:
+
+`sudo rc-service {{service_name}} restart`
+
+- Simulate running a service's custom command:
+
+`sudo rc-service --dry-run {{service_name}} {{command_name}}`
+
+- Actually run a service's custom command:
+
+`sudo rc-service {{service_name}} {{command_name}}`
+
+- Resolve the location of a service definition on disk:
+
+`sudo rc-service --resolve {{service_name}}`