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PyBOMBS (Python Build Overlay Managed Bundle System) is the GNU Radio install management system for resolving dependencies and pulling in out-of-tree projects.


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PyBOMBS is good at building GNU Radio, UHD, and various Out of Tree (OOT) modules from source and then installing into a specified user directory rather than in the system files. PyBOMBS detects the user's Operating System and loads all of the prerequisites in the first stage of the build.

For those looking to dive right in, the following commands should install PyBOMBS and GNU Radio version 3.10 (from source) into a directory called ~/prefix-3.10 and was verified to work under a fresh Ubuntu 20.04 and 22.04 install.

sudo apt-get install python3-pip
sudo pip3 install pybombs
pybombs auto-config
pybombs recipes add-defaults
pybombs prefix init ~/prefix-3.10 -R gnuradio-default
source ~/prefix-3.10/

Because it's installing GNU Radio from source, the 5th step might take some time, for a quicker install see

Table of Contents

Installing PyBOMBS

Open a terminal window.

The commands given below containing 'apt' are ones for Debian, Ubuntu, and derivatives. For other operating systems:

  • Fedora - use dnf
  • RHEL/CentOS - use yum
  • Archlinux - use pacman
  • Check with your OS documentation for specific syntax.

If you don't have 'git', run the following command:

sudo apt install git

Using pip

You don't have to clone the PyBOMBS repository if you don't plan to contribute to PyBOMBS yourself.

Using Python2.7

If you do not have Python2.7, run the following commands:

sudo apt install python
sudo apt install python-pip

If you have previously installed PyBOMBS with Python3, run the following command:

sudo pip3 uninstall pybombs

and then run:

sudo pip install --upgrade git+

Using Python3

If you have previously installed PyBOMBS with Python2, run the following command:

sudo pip uninstall pybombs

Note: If you are building UHD-3.14 or previous, run the following commands:

sudo apt install python
sudo apt install python-pip
sudo pip install mako requests numpy

If you don't already have python3, run the following commands:

sudo apt install python3
sudo apt install python3-pip

and then run:

sudo pip3 install --upgrade git+

From source using Python's setuptools

To clone the PyBOMBS source code, enter:

cd ~/
git clone
cd ~/pybombs

then, to build in user's directory, run:

python build

or, to install in the system directory, run:

sudo python install

This will install PyBOMBS and all required dependencies. See

python build --help
python install --help

for additional settings.

Executing PyBOMBS


There are several gnuradio recipes for use with the pybombs prefix command:

  • gnuradio38 builds GNU Radio 3.8 from the maint-3.8 branch
  • gnuradio39 builds GNU Radio 3.9 from the maint-3.9 branch
  • gnuradio310 builds GNU Radio 3.10 from the maint-3.10 branch
  • gnuradio-default builds the latest maintenance branch (currently maint-3.10)
  • gnuradio-main builds GNU Radio's main branch

In the following instructions, the notation {your_recipe} denotes your choice of recipe.

Folder/directory (prefix) definition

One of the main advantages of using PyBOMBS is the ability to specify a folder/directory within the user's account to contain all the files associated with the build. That allows the user to delete that one folder/directory and thereby remove everything associated with the build. No system files are affected.

In the following instructions, the notation {base_folder} denotes where to put the top level folder/directory. For example ~/gr38. See more information in the Prefixes section below.

Platform-specific instructions

Platforms that require special attention are listed here:

To run PyBOMBS

  1. Install PyBOMBS per the previous section.

  2. Apply a default configuration:

     pybombs auto-config
  3. Add a list of recipes, e.g., the default recipes:

     pybombs recipes add-defaults
  4. Install GNU Radio into your selected directory (the alias parameter is optional):

     pybombs prefix init ~/{base_folder} -R {your_recipe}

    Wait. The terminal will show the progress.

  5. Run GNU Radio Companion from your new folder:

     source ~/{base_folder}/

    or execute it without changing the current environment:

     pybombs run gnuradio-companion


A prefix is a directory into which packages are installed.

The prefix may be ~/prefix. Typically, the prefix resides inside your home directory so you can modify or delete prefixes easily without admin access. This is the recommended way of running PyBOMBS. Any directory may be a prefix, but it is highly recommended to choose a dedicated directory for this purpose.

Many developers have multiple prefixes. Instead if installing to ~/prefix, a common way is to have multiple prefixes, e.g., ~/prefix/default_prefix, ~/prefix/dev_prefix, etc.

Prefixes require a configuration directory to function properly. Typically, it is called .pybombs/ and is a subdirectory of the prefix. So, if your prefix is ~/prefix, there will be a directory called ~/prefix/.pybombs/ containing special files. The two most important files are the inventory file (inventory.yml) and the prefix-local configuration file (config.yml), but it can also contain recipe files that are specific to this prefix.

There is no limit to the number of prefixes. Indeed, it may make sense to have many prefixes, e.g. one for system-wide installation, one for a user-specific installation, and one for cross-compiling to a different platform.

When running PyBOMBS, you select the desired prefix using the -p switch. You can set a default prefix with the following command:

pybombs config default_prefix {prefix_name}

The first time you run pybombs prefix init, it will set this value for you.

Prefix Selection

Prefixes are selected by the following rules, in this order:

  1. Whatever is provided by the -p or --prefix command line switch
  2. The current directory
  3. The default prefix as defined by the default_prefix config switch

If no prefix can be found, most PyBOMBS operations will not be possible, but some will still work (for example, you can install all dependencies for a package from binary sources).

Initializing Prefixes

Any directory can function as a prefix, and PyBOMBS will make sure all the required files and directories are created. However, PyBOMBS provides a way to initialize a directory to be a full PyBOMBS prefix:

pybombs prefix init /path/to/prefix [-a alias]

This is similar to git init. The optional alias allows you to access the prefix with the alias instead of the full path. A typical value for the default prefix is ~/prefix/default, and then other prefixes also reside in ~/prefix alongside the default prefix.

After initializing a prefix, you can start to install to this prefix using the install command:

pybombs -p <alias> install <package>

PyBOMBS provides a way to not only initialize a raw prefix, but also configure it and install packages through a prefix recipe. These are selected using the -R switch on the command line:

pybombs prefix init /path/to/prefix [-a alias] [-R prefix-recipe]


An alias is an optionally assigned name to provide a short substitute for a prefix path. It can be created in one of two ways:

  • in the pybombs prefix init command, adding -a {alias_name} will equate the ~/{base_folder} with {alias_name}.

  • by adding a [prefix_aliases] section in a configuration file. The format is alias=/path/to/prefix. Once an alias is defined, it can be used in a command such as pybombs -p {alias_name} install <package> in place of the prefix path.

Configuring a prefix environment (e.g. for cross-compiling)

Setting environment variables directly:

For a quick setup of environment variables, you can use the pybombs config command:

pybombs config --env CC clang
pybombs prefix env
# ...lots of output...
# ...lots of output...

This will, by default, set an environment variable for all prefixes. You might want to set it for a specific one, in that case, specify the prefix:

pybombs -p default config --env CC clang

You can also edit the config files directly. In any config file that is read, a env: section can be added. This will set environment variables for any command (configure, build, make...) that is run within PyBOMBS.

Note that this will still use the regular system environment as well, but it will overwrite existing variables. Variable expansion can be used, so this will keep the original setting:

    LD_LIBRARY_PATH: ${LD_LIBRARY_PATH}:/path/to/more/libs

Note: Because this is a YAML file, remember to separate key/value pairs with colon (:), not an equals sign, as you would in a shell script.

In all cases, the environment variable PYBOMBS_PREFIX is set to the current prefix, and PYBOMBS_PREFIX_SRC is set to the source directory.

Use pybombs prefix env to show all environment variables as they would appear when commands are run inside the prefix.

Using an external script to set the environment

Inside the config section, a shell script can be defined that sets up an environment, which will then be used for commands running inside this prefix.


    # Other vars
    setup_env: /path/to/environment-setup-armv7ahf-vfp-neon-oe-linux-gnueabi

In this case, the environment from the calling shell session is not inherited.

Python version

PyBOMBS itself is developed to work with both Python 2 and 3. However, the Python version is not a one-dimensional problem: The prefix could be running a different version of Python than the system. A common use case for this is when the system's default version is Python 3, but a prefix was created to test software with Python 2 (or vice versa). In this case, the PyBOMBS executable will be executed by a different Python interpreter than will be used to run installed scripts.

To define the Python version of the prefix, there are multiple options:

  • If the prefix is also a Python virtualenv, the Python version is autodetected.
  • Use the python_ver prefix configuration option.

The Python version of the prefix will default to the interpreter version running the PyBOMBS script.

Installing packages

When you run a command such as

pybombs install gnuradio

PyBOMBS will initiate an installation procedure for the package. Since PyBOMBS can interact both with the system's package manager (e.g., apt, dnf, brew...) and install source packages, there need to be clearly defined rules about the order of operations. PyBOMBS will attempt to install packages following these rules:

  1. Is the package flagged explicitly for source installation? If so, put it into a queue for source package builds. Otherwise, attempt to install it from the system's package manager. If that fails, also put it into the queue for source package builds.
  2. Any package that is flagged for building from source is analysed to find the source build dependencies. For all of those packages, the same procedure is applied.
  3. Eventually, all binary installs are complete and the source installs are left. The source packages are put into a tree, so they can be installed starting at the lowest dependee.

Example: In the command above, the package gnuradio has two dependencies, uhd and boost. In a configuration file, uhd and gnuradio are flagged for building from source. PyBOMBS will put gnuradio and uhd into the source build queue, and then invoke the system's package manager to install boost. When the package boost is installed, PyBOMBS generates a source build tree, which in this case is a very simple tree: gnuradio <- uhd, meaning that the package gnuradio depends on the package uhd, so uhd needs to be installed first. PyBOMBS then executes a source build of uhd, then gnuradio (in that order) into the prefix.

(Note: The actual dependency structure for those packages is more complex and was simplified for this document).


Recipe Format

Recipes files are in YAML format. To write new recipes, the easiest way is to use other recipes as examples.

Important keys in the recipe files include:

  • inherit: This will load the values from a template file (*.lwt) before using the values from the recipe, to set up suitable defaults.
  • category: Can technically be anything, but certain categories carry certain meanings. In most cases, choose 'common'.


# This means the build/install works like any other cmake project:
inherit: cmake
# These dependencies are only for source builds:
- boost
- fftw
- cppunit
# There's more dependencies in the real repo, skipping for this example
description: Free and open source toolkit for software defined radio
category: common
# Its good practice to add one of these for all the installers we have:
  deb: gnuradio-dev
  pacman: gnuradio
  port: gnuradio
  portage: net-wireless/gnuradio
source: git+
# master is the default branch, but you can choose a different branch or tag here:
gitbranch: master
# Instead of a branch, you can also specify any commit:
#gitrev: 012345abc
# Another way to specify a commit is to append a rev, tag, or commit has to the
# source URL (git+https://.../gnuradio.git@abcd1234)
# Only when cloning the source code is this used, in that case, these args are
# appended to the git command that does the clone:
gitargs: --recursive
# Variables defined here can be used in various places in this recipe:
  config_opt: " -DENABLE_DOXYGEN=$builddocs "
# For static builds, we need to override the defaults from the cmake.lwt recipe:
configure_static: cmake .. -DCMAKE_BUILD_TYPE=$cmakebuildtype -DCMAKE_INSTALL_PREFIX=$prefix -DENABLE_STATIC_LIBS=True $config_opt

Recipe Management

Recipes can be stored in multiple locations, which easily allows to store separate recipe lists for specific projects.

If the same recipe can be found in more than one location, it will be chosen from the most specific. The precise order is (from more to less specific):

  • Recipe locations specified on the command line (Using the -r switch)
  • From the environment variable PYBOMBS_RECIPE_DIR
  • The current prefix (if available)
  • Global recipe locations

The command

pybombs recipes list-repos

will show the recipe locations in the order they're used (it will pick a recipe from the top line before it'll pick it from the bottom line).

This mechanism can be used to override recipes for certain prefixes. For example, the gnuradio.lwr file could be copied and adapted to use a different branch than the default recipe does. (Note that specific parts of recipes can also be overridden in the config.yml file, in the [packages] section).

Recipe management can be mostly done through the command line using the pybombs recipes command -- editing configuration files is possible, but often not necessary. Run

pybombs help recipes

for further information on the pybombs recipes command.

Remote and Local Recipe Locations

Recipe locations can be either local directories (in this case, PyBOMBS will simply read any .lwr file from this directory, without traversing into subdirectories), or a remote location. Remote locations can be:

  • git repositories
  • Remotely stored .tar.gz archives

Remote locations are copied into a local directory, so PyBOMBS can read the .lwr files locally. During normal operations, PyBOMBS will not try to read the remote location, so offline usage is still possible. This local cache of recipes is stored in the same directory as the location of the corresponding config file (e.g., if ~/.pybombs/config.yml declares a recipe called 'myrecipes', the local cache will be in ~/.pybombs/recipes/myrecipes).

Configuration Files

Typically, there are four ways to configure PyBOMBS:

  1. The global configuration file (e.g. /etc/pybombs/config.yml)
  2. The user-local configuration file (e.g. ~/.pybombs/config.yml)
  3. The prefix-local configuration file (e.g. ~/src/prefix/.pybombs/config.yml)
  4. By using the --config switch on the command line

Higher numbers mean higher priority. Conflicting options are resolved by choosing option values with higher priority.

config.yml File Format

The config.yml files are in YAML format. A typical file looks like this:

# All configuration options:
# (Run `pybombs config` to learn which options are recognized)
# You can edit these with `pybombs config` too
    default_prefix: default
    makewidth: 8 # Run on 8 cores
    # ... more options

# Prefix aliases:
    default: /home/user/src/pb-prefix/
    sys: /usr/local
    # pybombs prefix init -a <alias> will add one automatically here

# Prefix configuration directories:
    sys: /home/user/pb-default/
    # Typically, you don't need this, because the prefix configuration
    # directory is in <PREFIX>/.pybombs

# Recipe locations:
    myrecipes: /usr/local/share/recipes
    morerecipes: /home/user/pb-recipes
    remoterecipes: git+git://url/to/repo
    # You wouldn't usually hand-edit this section, but use 'pybombs recipes' to
    # manipulate it

# Package flags:
        forcebuild: True  # This will skip any packagers for this package
                          # and use a source build
        forceinstalled: False  # 'True' will always assume this package is
                               # installed and skip installing it
        # Any other option here will override whatever's in the
        # corresponding recipe (in this case, gnuradio.lwr)
        # You can set these with pybombs config --package gnuradio forcebuild False

# Like package flags, but applies flags to all packages
# in a certain category. 'common' is all OOTs.
        forcebuild: True  # This would force source builds for any package in the
                          # `common` category
        # Still works via pybombs config --category common forcebuild True

# Environment variables
    LD_LIBRARY_PATH: ${LD_LIBRARY_PATH}:/path/to/more/libs
    # You can also do pybombs config --env CC clang

git cache (reference repository)

Many packages specify git source repositories. Because there's a lot of git interaction, pybombs has some tools to make your life working with git easier.

You can set up a git cache, or reference repository, to store objects locally, and hence reduce clone times.

The simplest way to set this up is to run

pybombs git make-ref

It will create the reference repository (which will then be used in subsequent) clones, and configure your PyBOMBS accordingly. See

pybombs git make-ref --help

for more use cases.

If you already have a reference repository elsewhere, simply point PyBOMBS to it:

pybombs config git-cache /path/to/ref

Testing specific platforms

For testing distributions, PyBOMBS uses Docker containers. To make the statement "PyBOMBS is fully functional on platform XYZ", a specific container for said platform is run using the test framework. For example, to test Fedora 26, the following command can be run:

./ --skip-pylint --container=fedora26

The Dockerfiles are stored in tests/docker/*. It is easy to add containers to include more distributions, and submitting new Dockerfiles is heavily encouraged. Note that distributions can have subtle differences, and the Dockerfiles can be used as a reference on how exactly to set up PyBOMBS on a specific distribution.

If the tests pass, a distribution is usually considered functional. This does not mean that everything will automatically work on someone's computer running this distribution, but that's usually because local settings weren't taken into account.


Copyright 2015-2019 Free Software Foundation, Inc.

This file is part of PyBOMBS

PyBOMBS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

PyBOMBS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with PyBOMBS; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Boston, MA 02110-1301, USA.