错误node.application:运行时发生致命错误。例外情况随之而来。

org.apache.commons.cli.MissingOptionException: Missing required option: f    
    at org.apache.commons.cli.Parser.checkRequiredOptions (Parser.java:299)
    at org.apache.commons.cli.Parser.parse (Parser.java:231)
    at org.apache.commons.cli.Parser.parse (Parser.java:85)
    at org.apache.flume.node.Application.main (Application.java:252)`ERROR node.Application: A fatal error occurred while running. Exception follows.

org.apache.commons.cli.MissingOptionException: Missing required option: f
at org.apache.commons.cli.Parser.checkRequiredOptions (Parser.java:299) at org.apache.commons.cli.Parser.parse (Parser.java:231) at org.apache.commons.cli.Parser.parse (Parser.java:85) at org.apache.flume.node.Application.main (Application.java:252)

上面的错误是我在运行这个命令之后最后得到的：
./bin/flume ng agent-n twitter代理-c conf-f/usr/lib/apache-flume-1.4.0-bin/conf/flume.conf
有人能帮我解决瘦的问题，这样我就可以流到hdfs的twitter数据请`