================================
Build Systems (Batch Processing)
================================

.. seealso::

   :doc:`Reference for build systems <../reference/build_systems>`
        Complete documentation on all available options, variables, etc.


.. warning::

   Build system selection is currently
   undergoing a rework in the dev channel.
   The following information may be outdated.

   See `this forum thread <http://www.sublimetext.com/forum/viewtopic.php?f=2&t=17471&sid=81fd17a6c886e151a3f69c0eaa87272d>`_ for details.


Build systems let you run your files
through external programs like
:program:`make`, :program:`tidy`, interpreters, etc.

Executables called from build systems
must be in your :const:`PATH`.
For more information about making sure
the :const:`PATH` seen by Sublime Text
is set correctly, see :ref:`troubleshooting-build-systems`.


File Format
===========

Build systems are JSON files
and have the extension ``.sublime-build``.

Example
-------

Here's an example of a build system:

.. code-block:: js

    {
        "cmd": ["python", "-u", "$file"],
        "file_regex": "^[ ]*File \"(...*?)\", line ([0-9]*)",
        "selector": "source.python"
    }

``cmd``
    Required. This option contains the actual command line
    to be executed::

        python -u /path/to/current/file.ext

``file_regex``
    A Perl-style regular expression
    to capture error information
    from an external program's output.
    This information is used
    to help you navigate through error instances with :kbd:`F4`.

``selector``
    If the **Tools | Build System | Automatic** option is set,
    Sublime Text will automatically find
    the corresponding build system for the active file
    by matching ``selector`` to the file's scope.

In addition to options,
you can use some variables in build systems too,
as we have done above with ``$file``,
which expands to the active buffer's filename.


Where to Store Build Systems
============================

Build systems must be located somewhere
under the :file:`{Packages}` folder
(e.g. :file:`{Packages}/User`).
Many packages include their own build systems.


Running Build Systems
=====================

Build systems can be run by pressing :kbd:`F7`
or from **Tools → Build**.