Hadoop initial set up doesn't work

[Vincenzo Gulisano <vi...@gmail.com>]

Greetings,
I'm trying to setup HDFS on a single-node cluster. I've tried several
tutorials, but all of them lead to the same problem.
After the setup I can check that everything is working using:

jps
...
17421 NameNode
17519 DataNode
17611 SecondaryNameNode
17685 JobTracker
17778 TaskTracker
18425 Jps
...

AND

sudo netstat -plten | grep java
...
tcp        0      0 127.0.0.1:54310         0.0.0.0:*
LISTEN      1062       346907      17421/java      (namenode)
tcp        0      0 127.0.0.1:54311         0.0.0.0:*
LISTEN      1062       347480      17685/java      (job tracker)
...

The log files, too, don't report any error.
The problem I get is that running /bin/hadoop dfs -ls (or copyFromLocal,
etc.) the command is not executed, it just remains here and doesn't complete
/ exit.
No errors are reported in the log files.
Have someone faced this problem or knows what can be it solution?

Thanks in advance,
best regards