Eclean

eclean is a tool for cleaning Portage source files and binary packages. It is part of the package and managed by the Portage-Tools project.

Emerge
Install :

Usage
By default, source files are located in the directory, while binary packages are located in the  directory. The locations for each can be changed by altering the DISTDIR and the PKGDIR variables respectively in. Both locations can grow quite big if not periodically cleaned; this is the reason was created.

Full options list
Use eclean --help to see full action summary, options list, and usage breakdown:

Cleaning distfiles
Clean the source files directory by passing the  argument:

Or by running the short option:

Cleaning packages
For the directory with the binary packages use the following command instead:

Or by running the short option:

By default, source files and binary packages corresponding to any ebuild in the current Portage tree will not be deleted. This way, system administrators can easily downgrade a package or install a previously removed package, provided the package is still in the current Portage tree.

As an example, suppose packages foo-1.0 and foo-1.1 are both in the Portage tree. After updating from foo-1.0 to foo-1.1, run : source files for both versions will be kept, so if a problem occurs with foo-1.1 then the user can easily re-install foo-1.0 without re-downloading anything.

The other possible case is installing a previously removed package. Suppose that a package foo (any version) is installed on the system. After (inadvertently) removing it and running, the source files for foo will be kept, so it can be re-installed without re-downloading anything.

The same examples also apply for binary packages.

To save more disk space, add the  option: every source file or binary package that does not correspond to some currently installed package with version will be deleted. Please notice that this way users will not be protected in case they need to downgrade a package or re-install a previously removed package.

As an alternative, use both the  and the   options: every source file or binary package that does not correspond to some currently installed package (version does not matter) will be deleted. This still will not protect in case a re-install of a previously removed package is needed, but it will protect the sources if the package needs to be downgraded later.

For more details read the eclean(1) man page: