Use Software Modules¶

Overview¶

Load and manage software in the HPC environment using the modules system.

Before you begin¶

Make sure:

you can log into the HPC system
(see: Log into HPC)
you know which software you want to use
you have access to the environment where modules are available

Steps¶

1. Log into HPC¶

ssh <username>@hpc.uct.ac.za

2. Check which modules are currently loaded¶

module list

This shows the software modules currently active in your shell session.

3. Search for available software¶

To search for a package or software family:

module avail

If the module system supports filtered search, you can also use:

module avail <software-name>

Replace <software-name> with the name of the software you want.

4. Load a module¶

Load the required software module:

module load <module-name>

Replace <module-name> with the full module name shown by module avail.

Example:

module load <software-name>/<version>

5. Confirm that the module is loaded¶

module list

You should now see the module in the list of active modules.

If the software provides a command-line executable, you can also verify it directly:

which <command-name>

Replace <command-name> with the command you expect to run.

6. Run your software¶

Once the module is loaded, run your command as needed.

Example pattern:

<command-name> --help

This is a simple way to confirm that the software is available in your current session.

7. Unload a module when no longer needed¶

To remove a module from your current session:

module unload <module-name>

8. Reset your module environment if needed¶

To clear all currently loaded modules:

module purge

Use this if: - you want a clean environment - you need to avoid conflicts between loaded modules

Verify¶

Check that:

the required module appears in module list
the software command is available with which <command-name>
the software runs successfully in your session or job script

Troubleshooting¶

Module not found¶

Possible causes:

the module name is incorrect
the software is not available on the system
the version name is incorrect

Check again with:

module avail

Software command still not available after loading¶