layman是一种overlay manager，Overlays 的添加通常是通过编辑/etc/
make.conf的 PORTDIR_OVERLAY="" 来管理，但是在sabayon是使用Layman进行管理。
在
终端输入：
layman --help（灰色使用频率较高）
显示如下：
引用:
Usage:
layman -a/-d/-S|overlay
layman -f [-o url]
layman -l|-L
其中
layman -S的作用类似emerge --sync 更新syncs下所有已经
安装的overlaysOptions:
引用:
--version show program's version number and exit
-h, --help show this help message and exit
<Actions>:
-a ADD, --add=ADD Add the given overlay from the cached remote list to
your locally installed overlays.. Specify "ALL" to add
all overlays from the remote list.
-d DELETE, --delete=DELETE
Remove the given overlay from your locally installed
overlays. Specify "ALL" to remove all overlays
-s SYNC, --sync=SYNC
Update the specified overlay. Use "ALL" as parameter
to synchronize all overlays
-i INFO, --info=INFO
Display information about the specified overlay.
-S, --sync-all Update all overlays.
-L, --list List the contents of the remote list.
-l, --list-local List the locally installed overlays.
-f, --fetch Fetch a remote list of overlays. This option is
deprecated. The fetch operation will be performed by
default when you run sync, sync-all, or list.
-n, --nofetch Do not fetch a remote list of overlays.
-p PRIORITY, --priority=PRIORITY
Use this with the --add switch to set the priority of
the added overlay. This will influence the sorting
order of the overlays in the PORTDIR_OVERLAY variable.
<Path options>:
-c CONFIG, --config=CONFIG
Path to the config file [default:
/etc/layman/layman.cfg].
-o OVERLAYS, --overlays=OVERLAYS
The list of overlays [default:
http://www.gentoo.org/proj/en/overlays/layman-
global.txt].
<Output options>:
-v, --verbose Increase the amount of output and describe the
overlays.
-q, --quiet Yield no output. Please be careful with this option:
If the processes spawned by layman when adding or
synchronizing overlays require any input layman will
hang without telling you why. This might happen for
example if your overlay resides in subversion and the
SSL certificate of the server needs acceptance.
-N, --nocolor Remove color codes from the layman output.
-Q QUIETNESS, --quietness=QUIETNESS
Set the level of output (0-4). Default: 4. Once you
set this below 2 the same warning as given for --quiet
applies!
-k, --nocheck Do not check overlay definitions and do not issue a
warning if description or contact information are
missing.
<Debugging options>:
Control the debugging features of layman
--debug Activates debugging features.
--debug-level=DEBUG_LEVEL
A value between 0 and 10. 0 means no debugging
messages will be selected, 10 selects all debugging
messages. Default is "4".
--debug-verbose=DEBUG_VERBOSE
A value between 1 and 3. Lower values yield less
verbose debugging output. Default is "2".
--debug-methods=DEBUG_METHODS
Limits the methods that will return debugging output.
The function name is sufficient and there is
nodifference between class methods or general
functions. Several methods can be specified by
seperating them w with a comma. Default is "*" which
specifies all methods.
--debug-classes=DEBUG_CLASSES
Limits the classes that will return debugging output.
Specify only the class name not including the modules
in which the class is defined (e.g. MyModule.main.Main
should only be represented by "Main"). Severalclasses
can be specified by seperating them with a comma.
Default is "*" which specifies all classes.
--debug-variables=DEBUG_VARIABLES
Limits the variables that will return debugging
output. Several variables can be specified by
seperating them with a comma. Default is "*" which
specifies all variables.
--debug-class-vars In default mode the debugging code will only return
information on the local variable which does not
include the class variables. Use this switch to add
all values that are provided by "self".
--debug-nocolor Deactivates colors in the debugging output.
