How to Write a Gentoo ebuild: A Step-by-Step Guide

3 min readMar 11, 2023

Gentoo is a Linux distribution known for its flexibility and ability to be customized to suit the needs of the user. One of the ways users can customize their Gentoo system is by writing their own ebuilds. An ebuild is a script that defines how a package should be built and installed on a Gentoo system.

In this guide, I’ll walk you through the process of writing an ebuild from scratch. I’ll also provide an example ebuild for you to reference.

Step 1: Set up your environment

Before you start writing your ebuild, make sure you have the necessary tools installed. You’ll need app-portage/repoman and dev-util/pkgcheck to help you test and validate your ebuild.

Step 2: Create the ebuild file

To create an ebuild, you’ll need to create a new file with the .ebuild extension in the appropriate category directory under /usr/portage. The filename should follow the format package-name-version.ebuild.

For example, let’s say I want to write an ebuld for version 1.0.0 of a package called my-package. I would create a new file called my-package-1.0.0.ebuld in the appropriate category directory.

Step 3: Define metadata

At the top of your ebuld file, you’ll need to define some metadata. This includes variables such as EAPI, which specifies which version of the EAPI (Ebuld API) your ebuld is using; DESCRIPTION, which provides a brief description of the package; HOMEPAGE, which specifies the package’s homepage; and SRC_URI, which specifies where to download th

Here’s what my example metadata might look like:

EAPI=7
DESCRIPTION="My Package"
HOMEPAGE="https://example.com/my-package"
SRC_URI="https://example.com/downloads/${P}.tar.gz"

Step 4: Define dependencies

Next, you’ll need to specify any dependencies that your package has. You can do this using variables such as DEPEND and RDEPEND. These variables allow you to specify which other packages need to be installed before or after your package.

Here’s what my example dependencies might look like:

DEPEND="dev-libs/libfoo"
RDEPEND="${DEPEND}"

This specifies that my package depends on dev-libs/libfoo.

Step 5: Write functions

Now it’s time to start writing some code! An ebuld consists of several functions that define how the package should be built and installed. These functions include src_unpack, which specifies how to unpack the source code; src_compile, which specifies how to compile it; and src_install, which specifies how to install it on the user’s system.

Here’s what my example functions might look like:

src_unpack() {
    default
}
src_compile() {
    emake
}
src_install() {
    emake DESTDIR="${D}" install
}

These functions specify that I want to use the default unpacking method, use emake to compile the package, and use emake with the DESTDIR variable set to install it.

Step 6: Test your ebuild

Once you’ve written your ebuild, it’s important to test it thoroughly. You can use tools such as ebuild and repoman to make sure that your ebuild works correctly and follows Gentoo’s coding standards.

Step 7: Submit your ebuld

If you’re happy with your ebuld and want to contribute it back to Gentoo, you can submit it for review using tools such as Bugzilla or GitHub. Once approved, other users will be able to use your ebuld!

I hope this guide has been helpful in showing you how easy it can be to write an ebuild for Gentoo. With a little bit of practice, you’ll be able to create custom packages for your system in no time!

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How to Write a Gentoo ebuild: A Step-by-Step Guide

Written by Ronald Farrer