./hadoop dsfadmin –report运行出错

./hadoop dsfadmin –report运行出错，哪位知道原因分享一下：

$ ./hadoop dsfadmin –report
java.lang.NoClassDefFoundError: dsfadmin
Caused by: java.lang.ClassNotFoundException: dsfadmin
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: dsfadmin.  Program will exit.
Exception in thread "main"