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Customize Shell Environment¶

The action of customizing the shell environment from the default "bash" setting can in general be performed by running the change_shell command, together with the path to the shell executable present under the /bin system folder.

Change shell to ZSH¶

Here, we offer a specific example of the command necessary to change the shell from the default "bash" to the "zsh" option.

1	change_shell /bin/zsh

Dot Files¶

There exist several hidden system configuration files, or "dot-files", within the Login Home, such as the .bashrc and .bash_profile files. Caution is advised when modifying such files, since they can significantly affect the functionality of the shell environment. In case of uncertainty, we recommend the reader to consult relevant documentation manuals on the general Linux environment before implementing any change to these files.

NEVER remove the system content of the ".ssh" folder

We urge the user not to remove the default content of the files in the ".ssh" folder, since doing so can break the operations of the platform for the user.

Install a different version of python¶

It is sometimes necessary to use multiple versions or distributions of Python. The routines below demonstrate how to do it. We can also recommend using the pyenv ¹ tool, as an alternative.

via PyEnv¶

Install pyenv versioning tool into the user home directory using pyenv-installer ²:

1	curl -L https://github.com/pyenv/pyenv-installer/raw/master/bin/pyenv-installer \| bash

As the installation rountine directs, add the following likes to ~/.bashrc file:

# Load pyenv automatically by adding
# the following to ~/.bashrc:

export PATH="/home/<REPLACE_WITH_YOUR_USERNAME>/.pyenv/bin:$PATH"
eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

Now pyenv can be used to manage python versions all within the user home folder ~/.pyenv. Below we install python 3.8.0, and then create and source a virtual environment with it, that can be further managed with pip, for example:

pyenv install 3.5.0
pyenv virtualenv 3.5.0 .venv-3.5.0
source ~/.pyenv/versions/.venv-3.5.0/bin/activate
pip install matplotlib
...
# Deactivate the Virtual Environment when done
deactivate

python¶

Below is a quick tutorial on how to install python and pip in the userspace. This is helpful when prototyping and trying packages not yet supported system-wide.

Install Python to local directory

mkdir ~/python
cd ~/python
wget https://www.python.org/ftp/python/2.7.11/Python-2.7.11.tgz
tar zxfv Python-2.7.11.tgz
find ~/python -type d | xargs chmod 0755
cd Python-2.7.11

Compile the source following the official guidelines
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./configure --prefix=$HOME/python make && make install
Notice the prefix option, it is mandatory for this to work. The value of prefix option is to specify where to put the related output of make command, by default it is in the /usr/local/ but we use our home directory instead.
Next, update the environment variables to use our new Python. Edit ~/.bashrc_profile and add the following lines:
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export PATH=$HOME/python/Python-2.7.11/:$PATH export PYTHONPATH=$HOME/python/Python-2.7.11
Refresh the current session by running the command:
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source ~/.bashrc_profile
One might need to logout and login again for the environment to update properly.
At this point, one should be able to see the new python. To check, run this command:
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python --version

pip¶

Pip is a python package manager, as explained in the references here. Below are directives that allow for its installation to be used with the newly installed python above.

After installing Python locally, install pip.

1	wget --no-check-certificate https://bootstrap.pypa.io/get-pip.py -O - \| python - --user

After finishing the installation, update PATH variable. Open ~/.bashrc_profile and add the following line:
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export PATH=$HOME/.local/bin:$PATH
Reload the session by the command source ~/.bashrc_profile or logout and login again. Then, check if pip command is available:
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which pip

It should show a path pointing to your local directory: ~/.local/bin