.. _cli::p3-file-filter:


##############
p3-file-filter
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.. highlight:: perl


***********************************************
Filter a File Against Contents of a Second File
***********************************************



.. code-block:: perl

     p3-file-filter.pl [options] filterFile filterCol1 filterCol2 ...


Filter the standard input using the contents of a file. The output will contain only those rows in the input file whose key value
matches a value from the specified column of the specified filter file. To have the output contain only those rows in the input
file that do NOT match, use the \ ``--reverse``\  option. This is similar to :ref:`cli::p3-merge`, except that script operates on whole
lines instead of a set of key fields.

Parameters
==========


The positional parameters are the name of the filter file and the indices (1-based) or names of the key columns in the filter file.
If the latter parameter is absent, the value of the \ ``--col``\  parameter will be used (same name or index as the input file).

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

Additional command-line options are the following.


reverse
 
 Instead of only keeping input records that match a filter record, only keep records that do NOT match.
 


col
 
 The name or index of the key column in the input file. If more than one value is specified, the columns are matched one-for-one
 with the corresponding filter file columns.