Remove now-redundant explicit "logstash" command

logstash/content.md

@@ -13,7 +13,7 @@ Logstash is a tool that can be used to collect, process and forward events and l
 If you need to run logstash with configuration provided on the commandline, you can use the logstash image as follows:
 
 ```console
-$ docker run -it --rm logstash logstash -e 'input { stdin { } } output { stdout { } }'
+$ docker run -it --rm logstash -e 'input { stdin { } } output { stdout { } }'
 ```
 
 ## Start Logstash with configuration file
@@ -21,5 +21,5 @@ $ docker run -it --rm logstash logstash -e 'input { stdin { } } output { stdout
 If you need to run logstash with a configuration file, `logstash.conf`, that's located in your current directory, you can use the logstash image as follows:
 
 ```console
-$ docker run -it --rm -v "$PWD":/config-dir logstash logstash -f /config-dir/logstash.conf
+$ docker run -it --rm -v "$PWD":/config-dir logstash -f /config-dir/logstash.conf
 ```