Improve README; check-smtp
Check for SMTP connection.
-## Setting
+## Synopsis
+```
+check-smtp -H smtp.example.com -p 25 -w 3 -c 5 -t 10
+```
+
+## Installation
+
+First, build this program.
+
+```
+go get github.com/mackerelio/go-check-plugins
+cd $(go env GOPATH)/src/github.com/mackerelio/go-check-plugins/check-smtp
+go install
+```
+
+Or you can use this program by installing the official Mackerel package. See [Using the official check plugin pack for check monitoring - Mackerel Docs](https://mackerel.io/docs/entry/howto/mackerel-check-plugins).
+
+
+Next, you can execute this program :-)
```
-[plugin.checks.smtp]
-command = "/path/to/check-smtp -H smtp.example.com -p 25 -w 3 -c 5 -t 10"
+check-smtp -H smtp.example.com -p 25 -w 3 -c 5 -t 10
```
-## Options
+
+## Setting for mackerel-agent
+
+If there are no problems in the execution result, add s setting in mackerel-agent.conf .
+
+```
+[plugin.checks.check-smtp-sample]
+command = ["check-smtp", "-H", "smtp.example.com", "-p", "25", "-w", "3", "-c", "5", "-t", "10"]
+```
+
+## Usage
+### Options
```
-H, --host= Hostname (default: localhost)
@@ -26,3 +54,7 @@ command = "/path/to/check-smtp -H smtp.example.com -p 25 -w 3 -c 5 -t 10"
-c, --critical= Critical threshold (sec)
-t, --timeout= Timeout (sec) (default: 10)
```
+
+## For more information
+
+Please execute `check-smtp -h` and you can get command line options.
