Environment and Modules

Environment Variables

Environment variables configure your shell and applications: HOME is your home directory; PATH lists command directories.

To list the variables in your current environment, run:

env

To inspect an individual value, use echo, for example:

echo "$HOME"
echo "$PATH"

Environment output can include credentials or tokens set by applications. Check it before sharing it in a support ticket.

Select Software with Lmod

Lmod adjusts compiler and library paths in the current shell. It selects installed software; it does not install packages.

Discover and inspect modules

Command	Purpose
module list	Show loaded modules
module avail	Show available modules
module spider nvhpc	Search module versions and prerequisites
module help nvhpc-hpcx-cuda13-openmpi5/26.9	Read module help
module show nvhpc-hpcx-cuda13-openmpi5/26.9	Inspect environment changes without loading

Selected entries from the latest module avail output on ICARUS:

nvhpc/26.9 (D)
nvhpc-hpcx/26.9 (D)
nvhpc-hpcx-cuda13/26.9 (D)
nvhpc-hpcx-cuda13-openmpi5/26.9 (D)
nvhpc-hpcx-cuda13-openmpi4/26.9 (D)
nvhpc-nompi/26.9 (D)
nvhpc-byo-compiler/26.9 (D)
conda/24.x
mpi/openmpi/5.0.10-cuda
mpi/openmpi/5.0.10 (D)

(D) marks the default version.

Load the NVIDIA compiler and MPI stack

The following changes affect your current shell's software environment:

module purge
module load nvhpc-hpcx-cuda13-openmpi5/26.9
module list
mpicc --version

purge unloads modules (sticky modules may remain). Use one compatible compiler/MPI stack at a time rather than combining unrelated MPI modules.

mpicc wraps the C compiler. See Compilers for language wrappers and version checks.

Use the same environment for your jobs

Load the same module in your batch script. See the job templates.

To unload this module in your shell:

module unload nvhpc-hpcx-cuda13-openmpi5/26.9