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Setup Linux Toolchain from Scratch
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:link_to_translation:`zh_CN:[中文]`

The following instructions are alternative to downloading binary toolchain from Espressif website. To quickly setup the binary toolchain, instead of compiling it yourself, backup and proceed to section :doc:`linux-setup`.

.. note:: The reason you might need to build your own toolchain is to solve the Y2K38 problem (time_t expand to 64 bits instead of 32 bits).

Install Prerequisites
=====================

To compile with ESP-IDF you need to get the following packages:

- CentOS 7::

    sudo yum -y update && sudo yum install git wget ncurses-devel flex bison gperf python3 python3-pip cmake ninja-build ccache

CentOS 7 is still supported but CentOS version 8 is recommended for a better user experience.

- Ubuntu and Debian::

    sudo apt-get install git wget libncurses-dev flex bison gperf python3 python3-pip python3-setuptools python3-serial python3-cryptography python3-future python3-pyparsing python3-pyelftools cmake ninja-build ccache libffi-dev libssl-dev dfu-util

- Arch::

    sudo pacman -Sy --needed gcc git make ncurses flex bison gperf python-pyserial python-cryptography python-future python-pyparsing python-pyelftools cmake ninja ccache dfu-util

.. note::
    CMake version 3.5 or newer is required for use with ESP-IDF. Older Linux distributions may require updating, enabling of a "backports" repository, or installing of a "cmake3" package rather than "cmake".

Compile the Toolchain from Source
=================================

- Install dependencies:

  - CentOS 7::

        sudo yum install gawk gperf grep gettext ncurses-devel python3 python3-devel automake bison flex texinfo help2man libtool make

  - Ubuntu pre-16.04::

        sudo apt-get install gawk gperf grep gettext libncurses-dev python python-dev automake bison flex texinfo help2man libtool make

  - Ubuntu 16.04 or newer::

        sudo apt-get install gawk gperf grep gettext python python-dev automake bison flex texinfo help2man libtool libtool-bin make

  - Debian 9::

        sudo apt-get install gawk gperf grep gettext libncurses-dev python python-dev automake bison flex texinfo help2man libtool libtool-bin make

  - Arch::

        sudo pacman -Sy --needed python-pip

Create the working directory and go into it::

  mkdir -p ~/esp
  cd ~/esp

Download ``crosstool-NG`` and build it:

.. include:: /_build/inc/scratch-build-code.inc

.. note:: To create a toolchain with support for 64-bit time_t, you need to remove the ``--enable-newlib-long-time_t`` option from the ``crosstool-NG/samples/xtensa-esp32-elf/crosstool.config`` file in 33 and 43 lines.

Build the toolchain::

    ./ct-ng xtensa-esp32-elf
    ./ct-ng build
    chmod -R u+w builds/xtensa-esp32-elf

Toolchain will be built in ``~/esp/crosstool-NG/builds/xtensa-esp32-elf``. Follow :ref:`instructions for standard setup <setup-linux-toolchain-add-it-to-path-legacy>` to add the toolchain to your ``PATH``.

Python 2 deprecation
====================

Python 2 reached its `end of life <https://www.python.org/doc/sunset-python-2/>`_ and support for it in ESP-IDF will be removed soon. Please install Python 3.6 or higher. Instructions for popular Linux distributions are listed above.


Next Steps
==========

To carry on with development environment setup, proceed to :ref:`get-started-get-esp-idf`.