
Path Formats
************

The "paths:" section of the config file (see *Configuration*) lets you
specify the directory and file naming scheme for your music library.
Templates substitute symbols like "$title" (any field value prefixed
by "$") with the appropriate value from the track's metadata. Beets
adds the filename extension automatically.

For example, consider this path format string:
"$albumartist/$album/$track $title"

Here are some paths this format will generate:

* "Yeah Yeah Yeahs/It's Blitz!/01 Zero.mp3"

* "Spank Rock/YoYoYoYoYo/11 Competition.mp3"

* "The Magnetic Fields/Realism/01 You Must Be Out of Your Mind.mp3"

Because "$" is used to delineate a field reference, you can use "$$"
to emit a dollars sign. As with Python template strings, "${title}" is
equivalent to "$title"; you can use this if you need to separate a
field name from the text that follows it.


A Note About Artists
====================

Note that in path formats, you almost certainly want to use
"$albumartist" and not "$artist". The latter refers to the "track
artist" when it is present, which means that albums that have tracks
from different artists on them (like Stop Making Sense, for example)
will be placed into different folders! Continuing with the Stop Making
Sense example, you'll end up with most of the tracks in a "Talking
Heads" directory and one in a "Tom Tom Club" directory. You probably
don't want that! So use "$albumartist".

As a convenience, however, beets allows "$albumartist" to fall back to
the value for "$artist" and vice-versa if one tag is present but the
other is not.


Template Functions
==================

Beets path formats also support *function calls*, which can be used to
transform text and perform logical manipulations. The syntax for
function calls is like this: "%func{arg,arg}". For example, the
"upper" function makes its argument upper-case, so "%upper{beets
rocks}" will be replaced with "BEETS ROCKS". You can, of course, nest
function calls and place variable references in function arguments, so
"%upper{$artist}" becomes the upper-case version of the track's
artists.

These functions are built in to beets:

* "%lower{text}": Convert "text" to lowercase.

* "%upper{text}": Convert "text" to UPPERCASE.

* "%title{text}": Convert "text" to Title Case.

* "%left{text,n}": Return the first "n" characters of "text".

* "%right{text,n}": Return the last "n" characters of  "text".

* "%if{condition,text}" or "%if{condition,truetext,falsetext}": If
  "condition" is nonempty (or nonzero, if it's a number), then returns
  the second argument. Otherwise, returns the third argument if
  specified (or nothing if "falsetext" is left off).

* "%asciify{text}": Convert non-ASCII characters to their ASCII
  equivalents. For example, "café" becomes "cafe". Uses the mapping
  provided by the unidecode module. See the *asciify_paths*
  configuration option.

* "%aunique{identifiers,disambiguators}": Provides a unique string to
  disambiguate similar albums in the database. See *Album
  Disambiguation*, below.

* "%time{date_time,format}": Return the date and time in any format
  accepted by strftime. For example, to get the year some music was
  added to your library, use "%time{$added,%Y}".

* "%first{text}": Returns the first item, separated by ";" (a
  semicolon followed by a space). You can use
  "%first{text,count,skip}", where "count" is the number of items
  (default 1) and "skip" is number to skip (default 0). You can also
  use "%first{text,count,skip,sep,join}" where "sep" is the separator,
  like ";" or "/" and join is the text to concatenate the items.

* "%ifdef{field}", "%ifdef{field,truetext}" or
  "%ifdef{field,truetext,falsetext}": If "field" exists, then return
  "truetext" or "field" (default). Otherwise, returns "falsetext". The
  "field" should be entered without "$".

Plugins can extend beets with more template functions (see *Template
functions and values provided by plugins*).


Album Disambiguation
====================

Occasionally, bands release two albums with the same name (c.f.
Crystal Castles, Weezer, and any situation where a single has the same
name as an album or EP). Beets ships with special support, in the form
of the "%aunique{}" template function, to avoid placing two
identically-named albums in the same directory on disk.

The "aunique" function detects situations where two albums have some
identical fields and emits text from additional fields to disambiguate
the albums. For example, if you have both Crystal Castles albums in
your library, "%aunique{}" will expand to "[2008]" for one album and
"[2010]" for the other. The function detects that you have two albums
with the same artist and title but that they have different release
years.

For full flexibility, the "%aunique" function takes two arguments,
each of which are whitespace-separated lists of album field names: a
set of *identifiers* and a set of *disambiguators*. Any group of
albums with identical values for all the identifiers will be
considered "duplicates". Then, the function tries each disambiguator
field, looking for one that distinguishes each of the duplicate albums
from each other. The first such field is used as the result for
"%aunique". If no field suffices, an arbitrary number is used to
distinguish the two albums.

The default identifiers are "albumartist album" and the default
disambiguators are "albumtype year label catalognum albumdisambig". So
you can get reasonable disambiguation behavior if you just use
"%aunique{}" with no parameters in your path forms (as in the default
path formats), but you can customize the disambiguation if, for
example, you include the year by default in path formats.

One caveat: When you import an album that is named identically to one
already in your library, the *first* album—the one already in your
library— will not consider itself a duplicate at import time. This
means that "%aunique{}" will expand to nothing for this album and no
disambiguation string will be used at its import time. Only the second
album will receive a disambiguation string. If you want to add the
disambiguation string to both albums, just run "beet move" (possibly
restricted by a query) to update the paths for the albums.


Syntax Details
==============

The characters "$", "%", "{", "}", and "," are "special" in the path
template syntax. This means that, for example, if you want a "%"
character to appear in your paths, you'll need to be careful that you
don't accidentally write a function call. To escape any of these
characters (except "{", and "," outside a function argument), prefix
it with a "$".  For example, "$$" becomes "$"; "$%" becomes "%", etc.
The only exceptions are:

* "${", which is ambiguous with the variable reference syntax (like
  "${title}"). To insert a "{" alone, it's always sufficient to just
  type "{".

* commas are used as argument separators in function calls. Inside of
  a function's argument, use "$," to get a literal "," character.
  Outside of any function argument, escaping is not necessary: "," by
  itself will produce "," in the output.

If a value or function is undefined, the syntax is simply left
unreplaced. For example, if you write "$foo" in a path template, this
will yield "$foo" in the resulting paths because "foo" is not a valid
field name. The same is true of syntax errors like unclosed "{}"
pairs; if you ever see template syntax constructs leaking into your
paths, check your template for errors.

If an error occurs in the Python code that implements a function, the
function call will be expanded to a string that describes the
exception so you can debug your template. For example, the second
parameter to "%left" must be an integer; if you write
"%left{foo,bar}", this will be expanded to something like
"<ValueError: invalid literal for int()>".


Available Values
================

Here's a list of the different values available to path formats. The
current list can be found definitively by running the command "beet
fields". Note that plugins can add new (or replace existing) template
values (see *Template functions and values provided by plugins*).

Ordinary metadata:

* title

* artist

* artist_sort: The "sort name" of the track artist (e.g., "Beatles,
  The" or "White, Jack").

* artist_credit: The track-specific artist credit name, which may be a
  variation of the artist's "canonical" name.

* album

* albumartist: The artist for the entire album, which may be different
  from the artists for the individual tracks.

* albumartist_sort

* albumartist_credit

* genre

* composer

* grouping

* year, month, day: The release date of the specific release.

* original_year, original_month, original_day: The release date of the
  original version of the album.

* track

* tracktotal

* disc

* disctotal

* lyrics

* comments

* bpm

* comp: Compilation flag.

* albumtype: The MusicBrainz album type; the MusicBrainz wiki has a
  list of type names.

* label

* asin

* catalognum

* script

* language

* country

* albumstatus

* media

* albumdisambig

* disctitle

* encoder

Audio information:

* length (in seconds)

* bitrate (in kilobits per second, with units: e.g., "192kbps")

* format (e.g., "MP3" or "FLAC")

* channels

* bitdepth (only available for some formats)

* samplerate (in kilohertz, with units: e.g., "48kHz")

MusicBrainz and fingerprint information:

* mb_trackid

* mb_albumid

* mb_artistid

* mb_albumartistid

* mb_releasegroupid

* acoustid_fingerprint

* acoustid_id

Library metadata:

* mtime: The modification time of the audio file.

* added: The date and time that the music was added to your library.

* path: The item's filename.


Template functions and values provided by plugins
=================================================

Beets plugins can provide additional fields and functions to
templates. See the *Plugins* page for a full list of plugins. Some
plugin-provided constructs include:

* "$missing" by *Missing Plugin*: The number of missing tracks per
  album.

* "%bucket{text}" by *Bucket Plugin*: Substitute a string by the range
  it belongs to.

* "%the{text}" by *The Plugin*: Moves English articles to ends of
  strings.

The *Inline Plugin* lets you define template fields in your beets
configuration file using Python snippets. And for more advanced
processing, you can go all-in and write a dedicated plugin to register
your own fields and functions (see *Writing Plugins*).
