macOS 10.13。6 elasticsearch-6.4.0

kennethdeMBP:elasticsearch-6.4.0 kenneth$ ./bin/elasticsearch
Java HotSpot(TM) 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
Exception in thread "main" 2018-08-30 21:10:05,731 main ERROR No Log4j 2 configuration file found. Using default configuration (logging only errors to the console), or user programmatically provided configurations. Set system property 'log4j2.debug' to show Log4j 2 internal initialization logging. See https://logging.apache.org/log4j/2.x/manual/configuration.html for instructions on how to configure Log4j 2
SettingsException[Failed to load settings from [elasticsearch.yml]]; nested: ParsingException[Failed to parse object: expecting token of type [START_OBJECT] but found [VALUE_STRING]];
    at org.elasticsearch.common.settings.Settings$Builder.loadFromStream(Settings.java:1192)
    at org.elasticsearch.common.settings.Settings$Builder.loadFromPath(Settings.java:1165)
    at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:100)
    at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:95)
    at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86)
    at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124)
    at org.elasticsearch.cli.Command.main(Command.java:90)
    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93)
    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86)
Caused by: ParsingException[Failed to parse object: expecting token of type [START_OBJECT] but found [VALUE_STRING]]
    at org.elasticsearch.common.xcontent.XContentParserUtils.ensureExpectedToken(XContentParserUtils.java:78)
    at org.elasticsearch.common.settings.Settings.fromXContent(Settings.java:672)
    at org.elasticsearch.common.settings.Settings.access$500(Settings.java:84)
    at org.elasticsearch.common.settings.Settings$Builder.loadFromStream(Settings.java:1188)
    ... 8 more
kennethdeMBP:elasticsearch-6.4.0 kenneth$