在OpenEmbedded的发布套件中，使用bitbake-layers命令可以显示出现有的layers和priority：
$ bitbake-layers show-layers
layer path priority
==========================================================================
meta /local/openstlinux-18-01-23/layers/openembedded-core/meta 5
meta-oe /local/openstlinux-18-01-23/layers/meta-openembedded/meta-oe 6
这个bitbake-layers工具位于openembedded-core这个layer中，用来进行与layers相关的操作。
比如可以执行下列操作：
-
查看当前配置中的layers列表
-
将一个已存在的layer加入到现有配置中
-
创建一个新layer
此工具的help信息：
$ bitbake-layers --help
NOTE: Starting bitbake server...
usage: bitbake-layers [-d] [-q] [-F] [--color COLOR] [-h] <subcommand> ...
BitBake layers utility
optional arguments:
-d, --debug Enable debug output
-q, --quiet Print only errors
-F, --force Force add without recipe parse verification
--color COLOR Colorize output (where COLOR is auto, always, never)
-h, --help show this help message and exit
subcommands:
<subcommand>
show-layers show current configured layers.
show-overlayed list overlayed recipes (where the same recipe exists in another layer)
show-recipes list available recipes, showing the layer they are provided by
show-appends list bbappend files and recipe files they apply to
show-cross-depends Show dependencies between recipes that cross layer boundaries.
layerindex-fetch Fetches a layer from a layer index along with its dependent layers, and adds them to conf/bblayers.conf.
layerindex-show-depends
Find layer dependencies from layer index.
add-layer Add one or more layers to bblayers.conf.
remove-layer Remove one or more layers from bblayers.conf.
flatten flatten layer configuration into a separate output directory.
create-layer Create a basic layer
Use bitbake-layers <subcommand> --help to get help on a specific command
创建新layer后的建议操作：
-
更新README文件
-
更新conf/layer.conf文件中一些配置项，比如priority优先级
-
针对你的发布需要进行修改或添加组件
创建一个新layer：
要创建的话，需要指定新layer的位置，名字，而layer的priority设置是可选的。
举例，以priority 7创建一个layer：
$ bitbake-layers create-layer --priority 7 ../layers/meta-st/meta-my-custo-layer
NOTE: Starting bitbake server...
Add your new layer with 'bitbake-layers add-layer ../layers/meta-st/meta-my-custo-layer'
$ cd ../layers/meta-st
$ tree meta-my-custo-layer
meta-my-custo-layer
├── conf
│ └── layer.conf
├── COPYING.MIT
├── README
└── recipes-example
└── example
└── example.bb
3 directories, 4 files
添加完成，可以使用show-layers来查看添加是否成功。
其他使用方式：
1，删除一个layer，使用remove-layer。
2，添加一个已有layer，使用add-layer。
3，查看当前配置中的recipes：show-recipes
列出所有的targets/recipes(.bb files):
$ bitbake-layers show-recipes
列出符合筛选条件的recipes：
$ bitbake-layers show-recipes "*libc*"
参考：