.. _installing_env_mod_c:

Installing environment modules without root permissions
=======================================================

This short guide will explain how to install the standard environment modules Tcl/C
software package without root permissions on a Linux or Mac OS X system,
together with Tcl on which it depends.

Tcl
~~~

#. Go to `<http://www.tcl.tk>`_ and download the latest Tcl sources.
   At the time of writing, the latest available Tcl version was 8.5.15,
   which can be downloaded from
   `here <http://prdownloads.sourceforge.net/tcl/tcl8.5.15-src.tar.gz>`_.
   The remainder of these commands will assume Tcl v8.5.15 is being
   installed, you may need to adjust them accordingly.
   **Note**: Stick to Tcl v8.5.x, don’t consider using the more recent
   v8.6.x or higher, since the environment modules package is not
   compatible with those Tcl versions.

#. Unpack the Tcl source tarball:

   .. code:: bash

       tar xfvz tcl8.5.15-src.tar.gz

#. Pick a location where you will install Tcl. It should be a directory
   you have write permissions on.
   My suggestion would be to use something like ``$HOME/.local/Tcl``.

#. Go to the ``unix`` subdirectory of the unpacked Tcl directory, and
   run the ``configure`` script using the ``--prefix`` option:

   .. code:: bash

       cd tcl8.5.15/unix
       ./configure --prefix=$HOME/.local/Tcl

   If you’re building Tcl and environment modules on Mac, you should run
   ``configure`` in the ``tcl8.5.15/macosx`` directory instead.

#. Next, build Tcl using the ``make`` command. If the system you are
   building on has multiple cores, running make in parallel will speed
   up the build. Just use the ``-j`` option, and pass it a degree of
   parallelism (just use the number of cores your system has available),
   e.g.:

   ::

       make -j 4

#. The final step consists of installing Tcl to the directory specified
   in step 4. To do this, simply run:

   .. code:: bash

       make install


**All done!** Now you are ready to build the environment modules package, which requires Tcl.

Environment Modules
~~~~~~~~~~~~~~~~~~~

#. Download the latest source tarball for the environment modules tools
   from http://modules.sourceforge.net/. At the time of writing,
   the latest available version is 3.2.10 which can be downloaded
   `from here <http://prdownloads.sourceforge.net/modules/modules-3.2.10.tar.gz>`_.

#. Unpack the downloaded source tarball:

   .. code:: bash

       tar xfvz modules-3.2.10.tar.gz

#. Configure the build, again use ``--prefix`` to specify where to
   install the environment modules tool in the end. If you needed to
   install Tcl by hand as outlined in the previous section, you’ll also
   need to specify where it was installed using the ``--with-tcl`` option:

   .. code:: bash

       cd modules-3.2.10
       ./configure --prefix=$HOME/.local/environment-modules --with-tcl=$HOME/.local/Tcl/lib

#. Build with ``make``, consider parallel build if your system is recent
   enough:

   .. code:: bash

       make -j 4

#. Install:

   .. code:: bash

       make install

Alright, now just one more thing...

Set up your environment
~~~~~~~~~~~~~~~~~~~~~~~

Because you’ve installed environment modules and Tcl in a non-default
location, you need to make sure your environment is setup up correctly
to use them.

To make a long story short, these are the commands you need to execute:

.. code:: bash

    export PATH=$HOME/.local/environment-modules/Modules/3.2.10/bin:$PATH
    export LD_LIBRARY_PATH=$HOME/.local/Tcl/lib:$LD_LIBRARY_PATH
    # adjust line below if you're using a shell other than bash, check with 'echo $SHELL'
    source $HOME/.local/environment-modules/Modules/3.2.10/init/bash

.. tip:: Add these three lines in your ``.bashrc`` file, that way they’ll be executed every time you log in.