The ``idf.py`` command-line tool provides a front-end for easily managing your project builds, deployment and debugging, and more. It manages several tools, for example:
- CMake_, which configures the project to be built.
- Ninja_, which builds the project.
-`esptool.py`_, which flashes the target.
The :ref:`Step 5. First Steps on ESP-IDF <get-started-configure>` contains a brief introduction on how to set up ``idf.py`` to configure, build, and flash projects.
``idf.py`` should be run in an ESP-IDF project directory, i.e., a directory containing a ``CMakeLists.txt`` file. Older style projects that contain a ``Makefile`` will not work with ``idf.py``.
This command creates a new component, which will have a minimum set of files necessary for building. The ``-C`` option can be used to specify the directory the component will be created in. For more information about components see the :ref:`Component CMakeLists Files <component-directories>`.
ESP-IDF supports multiple targets (chips). A full list of supported targets in your version of ESP-IDF can be seen by running ``idf.py --list-targets``.
``idf.py set-target`` will clear the build directory and re-generate the ``sdkconfig`` file from scratch. The old ``sdkconfig`` file will be saved as ``sdkconfig.old``.
It is also possible to pass the desired ``IDF_TARGET`` as an environment variable (e.g., ``export IDF_TARGET=esp32s2``) or as a CMake variable (e.g., ``-DIDF_TARGET=esp32s2`` argument to CMake or ``idf.py`` ). Setting the environment variable is a convenient method if you mostly work with one type of the chip.
To specify the default value of ``IDF_TARGET`` for a given project, please add the ``CONFIG_IDF_TARGET`` option to the project's ``sdkconfig.defaults`` file, e.g., ``CONFIG_IDF_TARGET="esp32s2"``. This value of the option will be used if ``IDF_TARGET`` is not specified by other methods, such as using an environment variable, a CMake variable, or the ``idf.py set-target`` command.
- Run CMake_ as necessary to configure the project and generate build files for the main build tool.
- Run the main build tool (Ninja_ or `GNU Make`). By default, the build tool is automatically detected but it can be explicitly set by passing the ``-G`` option to ``idf.py``.
Additionally, the command can be run with ``app``, ``bootloader`` and ``partition-table`` arguments to build only the app, bootloader or partition table as applicable.
This command removes the project build output files from the build directory, and the project will be fully rebuilt on next build. Using this command does not remove the CMake configuration output inside the build folder.
This command deletes the entire build directory contents, which includes all CMake configuration output. The next time the project is built, CMake will configure it from scratch. Note that this option recursively deletes **all** files in the build directory, so use with care. Project configuration is not deleted.
This command automatically builds the project if necessary, and then flash it to the target. You can use ``-p`` and ``-b`` options to set serial port name and flasher baud rate, respectively.
..note:: The environment variables ``ESPPORT`` and ``ESPBAUD`` can be used to set default values for the ``-p`` and ``-b`` options, respectively. Providing these options on the command line overrides the default.
``idf.py`` uses the ``write_flash`` command of ``esptool.py`` under the hood to flash the target. You can pass additional arguments to configure the flash writing process using the ``--extra-args`` option. For example, to `write to an external SPI flash chip <https://docs.espressif.com/projects/esptool/en/latest/esptool/advanced-options.html#custom-spi-pin-configuration>`_, use the following command: ``idf.py flash --extra-args="--spi-connection <CLK>,<Q>,<D>,<HD>,<CS>"``. To see the full list of available arguments, run ``esptool.py write_flash --help`` or see the `esptool.py documentation <https://docs.espressif.com/projects/esptool/en/latest/esptool/index.html>`_.
Similarly to the ``build`` command, the command can be run with ``app``, ``bootloader`` and ``partition-table`` arguments to flash only the app, bootloader or partition table as applicable.
There are some situations, e.g. transferring the file to another machine and flashing it without ESP-IDF, where it is convenient to have only one file for flashing instead the several file output of ``idf.py build``.
The command ``idf.py merge-bin`` will merge the bootloader, partition table, the application itself, and other partitions (if there are any) according to the project configuration and create a single binary file ``merged-binary.[bin|hex]`` in the build folder, which can then be flashed later.
It is possible to output merged file in binary (raw), IntelHex (hex) and UF2 (uf2) formats.
The uf2 binary can also be generated by :ref:`idf.py uf2 <generate-uf2-binary>`. The ``idf.py uf2`` is functionally equivalent to ``idf.py merge-bin -f uf2``. However, the ``idf.py merge-bin`` command provides more flexibility and options for merging binaries into various formats described above.
Example usage:
..code-block:: bash
idf.py merge-bin -o my-merged-binary.bin -f raw
There are also some format specific options, which are listed below:
-``--flash-offset``: This option will create a merged binary that should be flashed at the specified offset, instead of at the standard offset of 0x0.
-``--fill-flash-size``: If set, the final binary file will be padded with FF bytes up to this flash size in order to fill the full flash content with the image and re-write the whole flash chip upon flashing.
-``--md5-disable``: This option will disable MD5 checksums at the end of each block. This can be useful for integration with e.g. `tinyuf2 <https://github.com/adafruit/tinyuf2>`__.
``idf.py`` will try to suggest hints on how to resolve errors. It works with a database of hints stored in :idf_file:`tools/idf_py_actions/hints.yml` and the hints will be printed if a match is found for the given error. The menuconfig target is not supported at the moment by automatic hints on resolving errors.
Multiple ``idf.py`` commands can be combined into one. For example, ``idf.py -p COM4 clean flash monitor`` will clean the source tree, then build the project and flash it to the target before running the serial monitor.
The order of multiple ``idf.py`` commands on the same invocation is not important, as they will automatically be executed in the correct order for everything to take effect (e.g., building before flashing, erasing before flashing).
To enable autocompletion for ``idf.py``, use the ``export`` command (:ref:`Step 4. Set up the environment variables <get-started-set-up-env>`). Autocompletion is initiated by pressing the TAB key. Type ``idf.py -`` and press the TAB key to autocomplete options.
This command forces CMake_ to be rerun regardless of whether it is necessary. It is unnecessary during normal usage, but can be useful after adding/removing files from the source tree, or when modifying CMake cache variables. For example, ``idf.py -DNAME='VALUE' reconfigure`` can be used to set variable ``NAME`` in CMake cache to value ``VALUE``.
This command deletes generated python byte code from the ESP-IDF directory. The byte code may cause issues when switching between ESP-IDF and Python versions. It is advised to run this target after switching versions of Python.
This command generates a UF2 (`USB Flashing Format <https://github.com/microsoft/uf2>`_) binary ``uf2.bin`` in the build directory. This file includes all the necessary binaries (bootloader, app, and partition table) for flashing the target.
This UF2 file can be copied to a USB mass storage device exposed by another ESP running the `ESP USB Bridge <https://github.com/espressif/esp-usb-bridge>`_ project. The bridge MCU will use it to flash the target MCU. This is as simple as copying (or "drag-and-dropping") the file to the exposed disk accessed by a file explorer in your machine.
The ``idf.py uf2`` command is functionally equivalent to ``idf.py merge-bin -f uf2`` described :ref:`above <merging-binaries>`. However, the ``idf.py merge-bin`` command provides more flexibility and options for merging binaries into various formats, not only uf2.
This command prints the contents of the ``otadata`` partition which stores the information about the currently selected OTA app slot. Refer to :doc:`/api-reference/system/ota` for more about the ``otadata`` partition.
To list all available root level options, run ``idf.py --help``. To list options that are specific for a subcommand, run ``idf.py <command> --help``, e.g., ``idf.py monitor --help``. Here is a list of some useful options:
Note that some older versions of CCache_ may exhibit bugs on some platforms, so if files are not rebuilt as expected, try disabling CCache_ and rebuilding the project. To enable CCache_ by default, set the ``IDF_CCACHE_ENABLE`` environment variable to a non-zero value.
-``--cmake-warn-uninitialized`` (or ``-w``) causes CMake to print uninitialized variable warnings found in the project directory only. This only controls CMake variable warnings inside CMake itself, not other types of build warnings. This option can also be set permanently by setting the ``IDF_CMAKE_WARN_UNINITIALIZED`` environment variable to a non-zero value.
-``--no-hints`` flag disables hints on resolving errors and disable capturing output.
It is possible to pass multiple arguments to ``idf.py`` via a file. The file or path to the file must be annotated with ``@`` at the beginning. Arguments in the file can be separated by newlines or spaces and are expanded exactly as if they had appeared in that order on the idf.py command line.
For example, let's have a file `custom_flash.txt`:
..code-block:: bash
flash --baud 115200
Then the command can be executed as: ``idf.py @custom_flash.txt monitor``
Arguments from a file can be combined with additional command line arguments, and multiple files annotated with ``@`` can be used simultaneously. For instance, if there is a second file ``another_config.txt``, both can be utilized by specifying ``idf.py @custom_flash.txt @another_config.txt monitor``.
A further example of how this argument file can be used, e.g., creating configuration profile files via @filename, is in the :example_file:`Multiple Build Configurations Example <build_system/cmake/multi_config/README.md>`.
