[doc] prefer to use STDIN signal in telegraf config

README.md

@@ -1,4 +1,4 @@
-# Telegraf execd vcstat input
+# vcstat
 
 vcstat is a VMware vSphere input plugin for [Telegraf](https://github.com/influxdata/telegraf) that gathers status and basic [stats](https://github.com/tesibelda/vcstat/blob/master/METRICS.md) from vCenter using govmomi library (in a similar way to [govc *.info](https://github.com/vmware/govmomi/blob/master/govc/USAGE.md) commands). You may use this input in parallel with Telegraf's vsphere input to complement the performance metrics it collects. With vcstat input's data you may be able to detect when a node goes from green to red, an HBA goes from link-up to link-down, to know the number of ports used by a Distributed Virtual Switch or create a basic capacity dashboard.
 
@@ -83,17 +83,17 @@ Use telegraf v1.14 or above so that execd input is available.
 ```
 ## Gather vSphere vCenter status and basic stats
 [[inputs.execd]]
-  command = ["/path/to/vcstat_binary", "-config", "/path/to/vcstat.conf"]
-  signal = "none"
+  command = ["/path/to/vcstat_binary", "--config", "/path/to/vcstat.conf"]
+  signal = "STDIN"
 ```
 
 You can optionally tell vcstat the input's interval by adding -poll_interval the_interval parameters to the command. By default it expects 1m interval. If you want 30s interval configure it like this:
 ```
 ## Gather vSphere vCenter status and basic stats
 [[inputs.execd]]
   interval = "30s"
-  command = ["/path/to/vcstat_binary", "-config", "/path/to/vcstat.conf", "-poll_interval", "30s"]
-  signal = "none"
+  command = ["/path/to/vcstat_binary", "--config", "/path/to/vcstat.conf", "--poll_interval", "30s"]
+  signal = "STDIN"
 ```
 Metric timestamp precision will be set according to the polling interval, so it will usually be 1s.