Issue 362:Make the default template string for the list command configurable.

beets/ui/commands.py

@@ -803,6 +803,8 @@ default_commands.append(import_cmd)
 
 # list: Query and show library contents.
 
+DEFAULT_LIST_FORMAT = '$artist - $album - $title'
+
 def list_items(lib, query, album, path, fmt):
     """Print out items in lib matching query. If album, then search for
     albums instead of single items. If path, print the matched objects'
@@ -838,7 +840,10 @@ list_cmd.parser.add_option('-p', '--path', action='store_true',
 list_cmd.parser.add_option('-f', '--format', action='store',
     help='print with custom format', default=None)
 def list_func(lib, config, opts, args):
-    list_items(lib, decargs(args), opts.album, opts.path, opts.format)
+    format = opts.format if opts.format is not None else \
+        ui.config_val(config, 'beets', 'list_format', 
+                      DEFAULT_LIST_FORMAT)
+    list_items(lib, decargs(args), opts.album, opts.path, format)
 list_cmd.func = list_func
 default_commands.append(list_cmd)
 

docs/reference/config.rst

@@ -171,6 +171,11 @@ section header:
     This option is historical and deprecated: it's almost always more
     appropriate to use ``import_move`` instead.
 
+``list_format``
+    Format to use when listing library content using ``beet list``. Defaults to
+    ``$artist - $album - $title``. The ``-f`` command-line option override this
+    setting.
+
 .. _path-format-config:
 
 Path Format Configuration