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MapReduce, mail # user - hadoop - running examples


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Re: hadoop - running examples
Andy Isaacson 2012-11-08, 23:33
On Thu, Nov 8, 2012 at 1:48 PM, Kartashov, Andy <[EMAIL PROTECTED]> wrote:
> When running examples, you bring them into HDFS. Say, you need to make some correction to a file, you need to make them on local FS and run $hadoop fs -put ... again. You cannot just make changes to files inside HDFS except for "touchz" a file, correct?

If you need to change existing data, you do need to write a new file,
or delete the old file then re-write it.  So as far as that goes, yes,
you cannot just make changes.

However, files can be appended to in HDFS, although I am not aware of
a "hdfs dfs -append" command to do append from the commandline. So
it's not quite correct to say that touchz is the only thing to change
an existing file.

-andy