Environment Modules¶

Software on BMRC is managed through the Lmod module system. Rather than installing packages globally or managing conflicting dependencies yourself, modules let you load pre-built, version-specific software into your shell environment on demand — and unload it just as easily.

Each module sets the necessary environment variables (PATH, LD_LIBRARY_PATH, PYTHONPATH, etc.) for a given piece of software, so tools are immediately available without any manual configuration.

Finding Available Software¶

To browse everything currently installed on the cluster:

module avail

This lists all available modules grouped by toolchain. The output can be long — it's often more useful to search by name.

To search for modules matching a keyword, use module spider:

module spider python

module spider performs a case-insensitive search across all module names and descriptions and is the recommended way to discover software. It will also tell you if a module requires other modules to be loaded first.

To narrow down module avail output to a specific pattern (useful for quick tab-complete style lookups):

module avail Python

OR

module spider Python

Filtering by Pattern¶

For more flexible searching — for example, finding all Python-related modules regardless of capitalisation — you can pipe the output through grep:

module avail 2>&1 | tr ' ' '\n' | grep -i python

Why 2>&1?

Lmod writes its output to stderr rather than stdout, so you need to redirect stderr to stdout before piping.

Loading and Unloading Modules¶

Once you've identified the module you need:

module load Python/3.11.3-GCCcore-12.3.0

It's good practice to specify the full versioned name (as shown by module spider) rather than just module load Python, which will load a default version that may change over time.

To see what modules you currently have loaded:

module list

To unload a specific module:

module unload Python/3.11.3-GCCcore-12.3.0

To unload all currently loaded modules and start fresh:

module purge

Module Naming Conventions¶

Module names on BMRC follow the EasyBuild convention:

<Software>/<Version>-<Toolchain>

For example, Python/3.11.3-GCCcore-12.3.0 is Python 3.11.3 built against the GCCcore-12.3.0 compiler toolchain. Some modules have no toolchain suffix (e.g. git/2.41.0) — these are typically pre-built binaries or system-independent tools.

Quick Reference¶

Command	Description
`module avail`	List all available modules
`module spider <name>`	Search for a module by name or keyword
`module load <name>`	Load a module
`module list`	Show currently loaded modules
`module unload <name>`	Unload a specific module
`module purge`	Unload all modules