.. include:: ../header.txt

.. _source:

:command:`source`
===========================

.. index:: source
.. program:: source
.. describe:: source

    Execute a shell script using the current shell.

SYNOPSIS

    :command:`source` script [ARGS ...]

    :command:`\.\ ` script [ARGS ...]

.. note::
    
    The :command:`source` command and a period followed by a space, `\.\ `, 
    are equivalent.

The shell script is ran within the current shell.  That is to say, the
shell does not first `fork()` and start a new shell to run the script.  The
primary reason for *sourcing* a script is if the script will assign
environment variables.  By using :command:`source`, the variables may be set in
the current shell.

There is sometimes confusion between :command:`source` and :command:`exec`,
because :command:`exec` also does not `fork()` first.  The intent of
:command:`exec` is to replace the shell with a new program, i.e., the current
shell does not run again.