diff --git a/config.go b/config.go
index bfae5df..53f497b 100644
--- a/config.go
+++ b/config.go
@@ -58,7 +58,7 @@ func getLogLevel(priority string) (Priority, error) {
 	return DEBUG, fmt.Errorf("'%s' is unsupported log priority", priority)
 }
 
-func LoadConfig(filename string) (*Config, error) {
+func LoadConfig(filename, logStreamName string) (*Config, error) {
 	configBytes, err := ioutil.ReadFile(filename)
 	if err != nil {
 		return nil, err
@@ -113,7 +113,9 @@ func LoadConfig(filename string) (*Config, error) {
 
 	config.LogGroupName = fConfig.LogGroupName
 
-	if fConfig.LogStreamName != "" {
+	if logStreamName != "" {
+		config.LogStreamName = logStreamName
+	} else if fConfig.LogStreamName != "" {
 		config.LogStreamName = fConfig.LogStreamName
 	} else {
 		// By default we use the instance id as the stream name.
diff --git a/main.go b/main.go
index c956eb2..369b9b0 100644
--- a/main.go
+++ b/main.go
@@ -10,6 +10,7 @@ import (
 )
 
 var help = flag.Bool("help", false, "set to true to show this help")
+var logStreamName = flag.String("S", "", "AWS log stream name")
 
 func main() {
 	flag.Parse()
@@ -40,7 +41,7 @@ func usage() {
 }
 
 func run(configFilename string) error {
-	config, err := LoadConfig(configFilename)
+	config, err := LoadConfig(configFilename, *logStreamName)
 	if err != nil {
 		return fmt.Errorf("error reading config: %s", err)
 	}