There are multiple locations where portage looks for set configuration files, which are usually named sets.conf. Not all of these locations have to contain a sets.conf, missing files are simply ignored. At first it looks for the default configuration in /usr/share/portage/config. The default config includes sets that are expected on all systems and often critical for normal operation, like world, system or security. After that it will read repository specific configurations from PORTDIR and PORTDIR_OVERLAYthat might include definitions of sets included in the repository. Finally a system-specific set configuration may reside in /etc/portage to either define additional sets or alter the default and repository sets. Unlike other Portage configuration files sets.conf uses Pythons ConfigParser module, which implements the syntax usually found in .ini files. At it's core it allows various named sections that each can contain any number of key-value pairs, see the Python documentation for the full details. In a sets.conf file, a section can define either a single package set, or a complete class of sets. These cases are handled in different ways, and will be explained in detail in the following sections. The configuration of a single set can be very simple as in most cases it only requires a single option class to be complete Technically the class option isn't stricly required, but it should always be used as the default handler might be changed in future versions. That option defines which handler class should be used to create the set. Another universal option available for single sets is name, however it's usually not needed as the name of the set is generated from the section name if name is missing. Some handler classes might require additional options for their configuration, these will be covered later in this chapter. Here are a few examples for single sets taken from the default configuration file: # The classic world set [world] class = portage.sets.files.WorldSet # The classic system set [system] class = portage.sets.profiles.PackagesSystemSet As configuring each single set manually could be quite annoying if you want many sets with the same options Portage also allows to define whole classes of sets in a single section. Like with single sets each section still requires the class option, but to indicate that the section should generate multiple sets it's also necessary to set the multiset option to true. As it doesn't make much sense to specify a single name for multiple sets the name option isn't available for multiset sections. Most handler classes will have a reasonable default for generating names, and usually you can (but don't have to) set the name_pattern option to change the naming rules. That option generally has to include a (handler-specific) placeholder that will be replaced with a unique identifier (e.g. for category sets the category name). As with single sets handler classes might require and/or support additional options, these will be discussed later. Some examples for multiset configurations: # generate a set for each file in /etc/portage/sets # this section is also in the default configuration [user sets] class = portage.sets.files.StaticFileSet multiset = true directory = /etc/portage/sets # Generate a set for each category that includes all installed packages # from that category. The sets will be named <category>/* [installed category packages] class = portage.sets.dbapi.CategorySet multiset = true repository = vartree name_pattern = $category/* The following sections contain the available handler classes that can be used for the class option in sets.conf, together with a description about required and optional configuration options for single and multi set configurations. Note that not all classes support both configuration styles. This class implements a simple file based package set. All atoms from configured file are used to form the set, and currently only simple and versioned atoms are supported (no use conditionals or any-of constructs). For descriptive purposes the file can be accompanied by a file with the same name plus a .metadata suffix which can contain metadata sections for description, author, location and so on. Each section has the form key: value where value can contain multiple lines. Therefore sections have to be separated by blank lines. For example: description: This is a somewhat longer description than usual. So it needs more than one line. homepage: http://www.foobar.org author: John Doe <john@doe.com> In a single set configuration this class supports the following options: filename: Required. Specifies the path to the file that should be used for the package set. In a multi set configuration this class supports the following options: directory: Optional, defaults to /etc/portage/sets. Specifies the path to a directory containing package set files. For each file (excluding metadata files) in that location a separate package set is created. name_pattern: Optional, defaults to sets/$name. This describes the naming pattern to be used for creating the sets. It must contain either $name or ${name}, which will be replaced by the filename (without any directory components). Similar to StaticFileSet, but uses Portage configuration files. Namely it can work with package.use, package.keywords, package.mask and package.unmask. It does not support .metadata files, but ignores the extra data (like USE flags or keywords) typically found in those files. In a single set configuration this class supports the following options: filename: See StaticFileSet In a multi set configuration this class supprts the following options: directory: Optional, defaults to /etc/portage. Specifies the path to a directory containing one or more of the following portage configuration files: package.use, package.keywords, package.mask or package.unmask. No other files in that directory will be used. name_pattern: Optional, defaults to sets/package_$suffix. This describes the naming pattern to be used for creating the sets. It must contain either $suffix or ${suffix}, which will be replaced by the file suffix (e.g. use or mask).