what's the difference between "hadoop fs" shell commands and "hdfs dfs" shell commands?

Question

Are they supposed to be equal?

but, why the "hadoop fs" commands show the hdfs files while the "hdfs dfs" commands show the local files?

here is the hadoop version information:

Hadoop 2.0.0-mr1-cdh4.2.1 Subversion git://ubuntu-slave07.jenkins.cloudera.com/var/lib/jenkins/workspace/CDH4.2.1-Packaging-MR1/build/cdh4/mr1/2.0.0-mr1-cdh4.2.1/source -r Compiled by jenkins on Mon Apr 22 10:48:26 PDT 2013

Answer 1

Following are the three commands which appears same but have minute differences

1. hadoop fs {args}
2. hadoop dfs {args}
3. hdfs dfs {args}

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  hadoop fs <args>

FS relates to a generic file system which can point to any file systems like local, HDFS etc. So this can be used when you are dealing with different file systems such as Local FS, (S)FTP, S3, and others

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  hadoop dfs <args>

dfs is very specific to HDFS. would work for operation relates to HDFS. This has been deprecated and we should use hdfs dfs instead.

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  hdfs dfs <args>

same as 2nd i.e would work for all the operations related to HDFS and is the recommended command instead of hadoop dfs

below is the list categorized as hdfs commands.

  namenode|secondarynamenode|datanode|dfs|dfsadmin|fsck|balancer|fetchdt|oiv|dfsgroups

So even if you use hadoop dfs , it will look locate hdfs and delegate that command to hdfs dfs