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This content explains the basic commands for using Spakc in HPC environments.
1. spack config blame packages
Shows where package configuration entries come from (packages.yaml) across different scopes (system, site, user, environment).
Similar to git blame — helps track the origin of a particular package setting.
2. spack compilers
Displays all compilers currently detected and registered by Spack.
Reads from ~/.spack/compilers.yaml or environment-specific configs.
3. spack compiler remove gcc@13.2.1
Removes the registered gcc@13.2.1 compiler from Spack’s config.
Does not uninstall gcc from the system — it only unregisters it from Spack.
4. spack compiler add /opt/cray/pe/gcc-native/12/bin
Registers a new compiler by scanning the given path for executables (gcc, g++, gfortran).
Commonly used in HPC systems for vendor-provided compilers (Cray, Intel, NVIDIA, AOCC, etc.).
5. spack compiler info gcc@13.2.1
Shows detailed information about the specified compiler.
Includes installation path, compiler executables, ABI support, environment variables, etc.
6. spack compiler list
Lists all compilers registered in Spack in a summarized format.
More concise than spack compilers.
7. spack spec fenics-dolfinx
Displays the dependency tree (specification) of the fenics-dolfinx package.
Shows compiler, package versions, build variants (+mpi, +cuda, etc.), and dependencies.
Very useful before installation to confirm the full spec.
8. spack concretize
Resolves and finalizes the package specification into a fully concrete form.
For example: fenics-dolfinx → fenics-dolfinx@0.8.0 %gcc@12.3.0 ^petsc@3.20.0 …
Ensures all versions and dependencies are pinned down before installation.
9. spack concretize --fresh -f
--fresh: Ignores cached concretizations and recomputes dependencies from scratch.
-f (force): Runs even if the environment is already concretized.
Useful after changing environment settings or resolving dependency conflicts.
10. spack env st
This is shorthand for spack env status.
Shows the currently active environment, or reports if no environment is active.
Useful for confirming whether you’re inside a particular Spack environment.
11. spack env deactivate (sometimes written as spack deactivate)
Deactivates the currently active Spack environment.
After running this, commands like spack install will no longer apply to that environment, but to the global Spack instance instead.
12. spack find
Lists all packages that are currently installed in your Spack installation.
By default, it shows unique specs (collapsed so that identical hashes/variants are grouped).
13. spack find -c
Stands for “concretized”.
Shows each package as it was fully concretized — including compiler, architecture, variants, and dependency hash.
Unlike plain spack find, this does not collapse identical specs, so you see the full details.