Zero Plugin
***********

The "zero" plugin allows you to null fields in files' metadata tags.
Fields can be nulled unconditionally or conditioned on a pattern
match. For example, the plugin can strip useless comments like "ripped
by MyGreatRipper."

The plugin can work in one of two modes:

* "fields": A blacklist, where you choose the tags you want to remove
  (used by default).

* "keep_fields": A whitelist, where you instead specify the tags you
  want to keep.

To use the "zero" plugin, enable the plugin in your configuration (see
Using Plugins).


Configuration
=============

Make a "zero:" section in your configuration file. You can specify the
fields to nullify and the conditions for nullifying them:

* Set "auto" to "yes" to null fields automatically on import. Default:
  "yes".

* Set "fields" to a whitespace-separated list of fields to remove. You
  can get the list of all available fields by running "beet fields".
  In addition, the "images" field allows you to remove any images
  embedded in the media file.

* Set "keep_fields" to *invert* the logic of the plugin. Only these
  fields will be kept; other fields will be removed. Remember to set
  only "fields" or "keep_fields"---not both!

* To conditionally filter a field, use "field: [regexp, regexp]" to
  specify regular expressions.

* By default this plugin only affects files' tags; the beets database
  is left unchanged. To update the tags in the database, set the
  "update_database" option to true.

For example:

   zero:
       fields: month day genre comments
       comments: [EAC, LAME, from.+collection, 'ripped by']
       genre: [rnb, 'power metal']
       update_database: true

If a custom pattern is not defined for a given field, the field will
be nulled unconditionally.

Note that the plugin currently does not zero fields when importing
"as-is".


Manually Triggering Zero
========================

You can also type "beet zero [QUERY]" to manually invoke the plugin on
music in your library.


Preserving Album Art
====================

If you use the "keep_fields" option, the plugin will remove embedded
album art from files' tags unless you tell it not to. To keep the
album art, include the special field "images" in the list. For
example:

   zero:
       keep_fields: title artist album year track genre images
