Various pages in this documentation refer to setting Zephyr-specific environment variables. This page describes how.
To set the environment variable MY_VARIABLE to foo for the
lifetime of your current terminal window:
.. tabs::
.. group-tab:: Linux/macOS
.. code-block:: console
export MY_VARIABLE=foo
.. group-tab:: Windows
.. code-block:: console
set MY_VARIABLE=foo
Warning
This is best for experimentation. If you close your terminal window, use another terminal window or tab, restart your computer, etc., this setting will be lost forever.
Using options 2 or 3 is recommended if you want to keep using the setting.
.. tabs::
.. group-tab:: Linux/macOS
Add the ``export MY_VARIABLE=foo`` line to your shell's startup script in
your home directory. For Bash, this is usually :file:`~/.bashrc` on Linux
or :file:`~/.bash_profile` on macOS. Changes in these startup scripts
don't affect shell instances already started; try opening a new terminal
window to get the new settings.
.. group-tab:: Windows
You can use the ``setx`` program in ``cmd.exe`` or the third-party RapidEE
program.
To use ``setx``, type this command, then close the terminal window. Any
new ``cmd.exe`` windows will have ``MY_VARIABLE`` set to ``foo``.
.. code-block:: console
setx MY_VARIABLE foo
To install RapidEE, a freeware graphical environment variable editor,
`using Chocolatey`_ in an Administrator command prompt:
.. code-block:: console
choco install rapidee
You can then run ``rapidee`` from your terminal to launch the program and set
environment variables. Make sure to use the "User" environment variables area
-- otherwise, you have to run RapidEE as administrator. Also make sure to save
your changes by clicking the Save button at top left before exiting. Settings
you make in RapidEE will be available whenever you open a new terminal window.
Choose this option if you don't want to make the variable's setting available to all of your terminals, but still want to save the value for loading into your environment when you are using Zephyr.
.. tabs::
.. group-tab:: Linux/macOS
Create a file named :file:`~/.zephyrrc` if it doesn't exist, then add this
line to it:
.. code-block:: console
export MY_VARIABLE=foo
To get this value back into your current terminal environment, **you must
run** ``source zephyr-env.sh`` from the main ``zephyr`` repository. Among
other things, this script sources :file:`~/.zephyrrc`.
The value will be lost if you close the window, etc.; run ``source
zephyr-env.sh`` again to get it back.
.. group-tab:: Windows
Add the line ``set MY_VARIABLE=foo`` to the file
:file:`%userprofile%\\zephyrrc.cmd` using a text editor such as Notepad to
save the value.
To get this value back into your current terminal environment, **you must
run** ``zephyr-env.cmd`` in a ``cmd.exe`` window after changing directory
to the main ``zephyr`` repository. Among other things, this script runs
:file:`%userprofile%\\zephyrrc.cmd`.
The value will be lost if you close the window, etc.; run
``zephyr-env.cmd`` again to get it back.
These scripts:
- set :envvar:`ZEPHYR_BASE` to the location of the zephyr repository
- adds some Zephyr-specific locations (such as zephyr's :file:`scripts`
directory) to your :envvar:`PATH` environment variable
- loads any settings from the ``zephyrrc`` files described above in
:ref:`env_vars_zephyrrc`.
You can thus use them any time you need any of these settings.
You can use the zephyr repository scripts zephyr-env.sh (for macOS and
Linux) and zephyr-env.cmd (for Windows) to load Zephyr-specific settings
into your current terminal's environment. To do so, run this command from the
zephyr repository:
.. tabs::
.. group-tab:: Linux/macOS
.. code-block:: console
source zephyr-env.sh
.. group-tab:: Windows
.. code-block:: console
zephyr-env.cmd
These scripts:
- set :envvar:`ZEPHYR_BASE` to the location of the zephyr repository
- adds some Zephyr-specific locations (such as zephyr's :file:`scripts`
directory) to your
PATHenvironment variable - loads any settings from the
zephyrrcfiles described above in :ref:`env_vars_zephyrrc`.
You can thus use them any time you need any of these settings.
Some :ref:`important-build-vars` can also be set in the environment. Here is a description of some of these important environment variables. This is not a comprehensive list.
.. envvar:: BOARD See :ref:`important-build-vars`.
.. envvar:: CONF_FILE See :ref:`important-build-vars`.
.. envvar:: SHIELD See :ref:`shields`.
.. envvar:: ZEPHYR_BASE See :ref:`important-build-vars`.
.. envvar:: EXTRA_ZEPHYR_MODULES See :ref:`important-build-vars`.
.. envvar:: ZEPHYR_MODULES See :ref:`important-build-vars`.
.. envvar:: ZEPHYR_BOARD_ALIASES See :ref:`gs-board-aliases`
The following additional environment variables are significant when configuring the :ref:`toolchain <gs_toolchain>` used to build Zephyr applications.
.. envvar:: ZEPHYR_SDK_INSTALL_DIR Path where Zephyr SDK is installed.
.. envvar:: ZEPHYR_TOOLCHAIN_VARIANT The name of the toolchain to use.
.. envvar:: {TOOLCHAIN}_TOOLCHAIN_PATH
Path to the toolchain specified by :envvar:`ZEPHYR_TOOLCHAIN_VARIANT`. For
example, if ``ZEPHYR_TOOLCHAIN_VARIANT=llvm``, use ``LLVM_TOOLCHAIN_PATH``.
(Note the capitalization when forming the environment variable name.)
You might need to update some of these variables when you :ref:`update the Zephyr SDK toolchain <gs_toolchain_update>`.
Emulators and boards may also depend on additional programs. The build system will try to locate those programs automatically, but may rely on additional CMake or environment variables to do so. Please consult your emulator's or board's documentation for more information. The following environment variables may be useful in such situations:
.. envvar:: PATH ``PATH`` is an environment variable used on Unix-like or Microsoft Windows operating systems to specify a set of directories where executable programs are located.