Reference

Last updated on 2026-10-28 | Edit this page

Commands

Start the 2025.06 stack where the repository is mounted:

BASH

source /cvmfs/software.eessi.io/versions/2025.06/init/lmod/bash

On the clusters, the first episode’s tab gives the site command. It is module load 2025 there. The container has no module named 2025.

BASH

module avail
module spider Python
module load Python/3.13.5-GCCcore-14.3.0
python3 --version
module list
module unload Python/3.13.5-GCCcore-14.3.0
module purge

python3 --version prints Python 3.13.5 for Python/3.13.5-GCCcore-14.3.0.

After module purge, the 2023.06 stack is a different load. Do not load it on top of 2025.06.

BASH

module load EESSI/2023.06
module load Python/3.11.5-GCCcore-13.2.0
python3 --version

That version line is Python 3.11.5.

Two variables set by the 2025.06 init script:

BASH

printf '%s\n' "$EESSI_VERSION"
printf '%s\n' "$EESSI_CVMFS_REPO"

They print 2025.06 and /cvmfs/software.eessi.io.

Glossary

EESSI: European Environment for Scientific Software Installations. A shared stack of scientific builds, distributed with CVMFS.
CVMFS: The file system that shows one directory tree on every machine that mounts it, and fetches a file the first time you use it. The tree in this lesson is /cvmfs/software.eessi.io.
shared stack: One curated set of builds. You select a build by loading a module. The files stay on the shared tree.
module: A name you load to put one build, and the libraries it needs, on your PATH.
Lmod: The module command used by EESSI. module and, after the init script, ml both talk to it.
module avail: Lists modules you can load right now. In a hierarchical stack that list is only the current level.
module spider: Searches every module, including names that module avail hides until another module is loaded.
module load: Puts one module into the current shell.
module unload: Removes one module from the current shell.
module purge: Removes all modules from the current shell. Run this before you switch stacks.
module list: Prints the modules loaded in the current shell.
module whatis: Prints the short description stored in a module file.
GCCcore: The compiler build that a module was linked against. It is part of the module name, as in Python/3.13.5-GCCcore-14.3.0.
CPU target: The processor family the init script selected, such as x86_64/intel/sapphirerapids on one host. Your line can name a different CPU.
Apptainer: The container tool used to start the EESSI client. The client has modules and has no sbatch.
EasyBuild: The tool that turns a recipe into a module file. Building modules is a different course.
QCG-PilotJob: A site module on the clusters. It is not part of EESSI 2025.06. module spider inside the EESSI tree does not find it.