add option to specify a shell when using ssm session

Author: AndreZiviani

internal/ssm/main.go

@@ -7,6 +7,7 @@ import (
 type Session struct {
 	Profile string `short:"p" long:"profile" env:"AWS_PROFILE" default:"default" description:"What profile to use"`
 	Region  string `short:"r" long:"region" env:"AWS_REGION" description:"What region to use, if not specified defaults to $AWS_DEFAULT_REGION or us-east-1"`
+	Shell   string `short:"s" long:"shell" default:"bash" description:"What shell to use on the remote instance"`
 }
 
 type PortForward struct {

internal/ssm/session.go

@@ -29,7 +29,13 @@ func (p *Session) DoSsm(ctx context.Context, id string) error {
 		return err
 	}
 
-	input := &awsssm.StartSessionInput{Target: &id}
+	input := &awsssm.StartSessionInput{
+		Target:       &id,
+		DocumentName: aws.String("AWS-StartInteractiveCommand"),
+		Parameters: map[string][]string{
+			"command": []string{p.Shell},
+		},
+	}
 	inputJson, err := json.Marshal(input)
 
 	ssmclient := awsssm.NewFromConfig(cfg)