Basic Environment
=================

You can define or modify your shell environment by editing ``~/.profile``, ``~/.bashrc`` and ``~/.bash_aliases``. Some examples/skeletons are available at ``/applis/PSMN/debian11/skeletons/``.

.. code-block:: bash

    cp /applis/PSMN/debian11/skeletons/profile ~/.profile
    cp /applis/PSMN/debian11/skeletons/bashrc ~/.bashrc


You may have to reconnect to take changes into account or ``source`` your modified file.

You can define your own aliases in ``~/.bash_aliases``:

.. code-block:: bash

    cp /applis/PSMN/debian11/skeletons/bash_aliases ~/.bash_aliases
    vi ~/.bash_aliases
    source ~/.bash_aliases
    aliases  # should show your new aliases

.. important::

    You may need to be aware of the order in cascading configuration files.
    It should be something like that:

    .. figure:: /_static/shell-startup.png
        :alt: expected shell startup
        :align: center
        :width: 400px

        Expected implementation

    Reality is ugly:

    .. figure:: /_static/shell-startup-actual.png
        :alt: actual shell startup
        :align: center
        :width: 400px

        Actual implementation

    Source `blog post <https://blog.flowblok.id.au/2013-02/shell-startup-scripts.html>`_

Finding softwares
=================

A large number of common utilities, libraries and softwares are already installed, either directly on the system:

* search in ``/usr/bin/``, ``/usr/lib/`` and ``/usr/lib/x86_64-linux-gnu/``

or by PSMN Staff:

* See :doc:`../modules_list` for a list of all available softwares, see :doc:`modular_environment` for how to use them.

However, **you can install and compile** your own versions of libraries and softwares in your ``$HOME``, or in your team shares (See :doc:`../filesystems/storages`).

Bash tips & tricks
==================

* Make sure that your ``PATH`` includes ``/bin`` and ``/usr/bin``. That is, when you need to add a new path to ``$PATH``, define it as follows : 

.. code-block:: bash

    export PATH=/a/new/path/to/add:$PATH

* aliases

The following commands should be placed on your, typically, /home/$USER/.bash_aliases file.

.. code-block:: bash

    alias l='ls -lF'      # Use long form and classify filetypes (one of */=>@|)
    alias la='ls -alF'    # Show hidden files, dot-files
    alias lh='ls -lFh'    # Human-readable file sizes
    alias lt='ls -lFt'    # sort by time
    alias ll='ls -alFth'  # all above :)

    alias du1='du -h -d1 .'

    alias hgrep='history | grep '  # grep from the bash history

    alias pending='squeue --me --states=PENDING --sort=S,Q --format="%.10i %.12P %.8j %.8u %.6D %.4C %.20R %Q %.19S" '  # my pending jobs
    alias running='squeue --me --states=RUNNING --format="%.10i %.12P %.8j %.8u %.2t %.10M %.6D %.4C %R %.19e" '  # my running jobs

* Perform mathematical computation in shell (``~/.bashrc`` functions):

.. code-block:: bash

    num()
    {
        echo $* | bc -l
    }

* Copy a file or directory in multiple destinations (``~/.bashrc`` functions):

.. code-block:: bash

    mcp()
    {
        echo "${*:2}" | xargs -n 1 cp $1
    }