.. _cli::p3-join:


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p3-join
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.. highlight:: perl


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Join Two Files on a Key Field
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.. code-block:: perl

     p3-join.pl [options] file1 file2


Join two files together on a single key field. Each record in the output will contain the fields from the first
file followed by the fields from the second file except for its key field. For each record in the first file,
every matching record in the second file will be appended. If no second-file records match, the first-file record
will be skipped.

Parameters
==========


The positional parameters are the names of the two files. If only one file is specified, the second file
will be taken from the standard input.

The standard input can be overriddn using the options in :ref:`cli-input-options`.

Additional command-line options are the following.


key1
 
 The index (1-based) or name of the key column in the first file. The default \ ``0``\ , indicating the last column.
 


key2
 
 The index (1-based) or name of the key column in the second file. The default is the value of \ ``--key1``\ .