hadoop命令无法识别

在运行一段时间后，突然报出hadoop不识别指令的错误。因为曾正确使用过，观察所在目录已变化，考虑是环境变量JAVA_HOME的问题。

/etc/profile中JAVA_HOME变量已修改。

考虑到hadoop2.2.0官方文档提及其他变量，如下补充。

vim /etc/profile

在/etc/profile文件的末尾加上以下配置
04	  
05	export HADOOP_DEV_HOME=/home/wyp/Downloads/hadoop/hadoop-2.2.0
06	export PATH=$PATH:$HADOOP_DEV_HOME/bin
07	export PATH=$PATH:$HADOOP_DEV_HOME/sbin
08	export HADOOP_MAPARED_HOME=${HADOOP_DEV_HOME}
09	export HADOOP_COMMON_HOME=${HADOOP_DEV_HOME}
10	export HADOOP_HDFS_HOME=${HADOOP_DEV_HOME}
11	export YARN_HOME=${HADOOP_DEV_HOME}
12	export HADOOP_CONF_DIR=${HADOOP_DEV_HOME}/etc/hadoop

结束后输入hadoop,返回：

Usage: hadoop [--config confdir] COMMAND
       where COMMAND is one of:
  fs                   run a generic filesystem user client
  version              print the version
  jar             run a jar file
  checknative [-a|-h]  check native hadoop and compression libraries availability
  distcp   copy file or directories recursively
  archive -archiveName NAME -p  *  create a hadoop archive
  classpath            prints the class path needed to get the
                       Hadoop jar and the required libraries
  daemonlog            get/set the log level for each daemon
 or
  CLASSNAME            run the class named CLASSNAME


Most commands print help when invoked w/o parameters.

原因：由于对前提准备hdfs安装，hadoop2.2.0未按照官方文档安装配置，出现很多隐藏问题