Update the instruction on using the system modules

[gkaf89]

For the email to the users:

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The method with which software is loaded has also changed.

1. Now there are environment modules

env/development/2023b env/release/default env/release/2020b

that load different software sets.

• The default env/release/default is loaded automatically and currently corresponds to env/release/2020b, so you won't observe any difference in your jobs.
• Loading another environment will replace your current environment.
• You can remove the environment module completely passing the --force flag to the module command.

IMPORTANT:
The default env/release/default environment will eventually point to the 2023b software set when it releases. Once it happens, most of your scripts that use modules will stop working (with The following module(s) are unknown: errors).
In preparation for the switch, add this at the beginning of your script if you are using the 2020b software set :

module load env/release/2020b

Note: If you don't know which software set your are using, it is likely that you are using 2020b by default.

2. You have access to an EESSI module (https://hpc-docs.uni.lu/software/eessi/), a common stack of scientific software installations for HPC systems. Load the module with

module load EESSI

to access the modules distributed by EESSI.