Spack Commands Cheat Sheet

`spack info`

Purpose: Provides detailed information about a specific package.
Usage: spack info <package_name>
Description:
Displays metadata for a package, including:
- Available versions
- Variants (optional features or configuration options)
- Dependencies
- Compiler compatibility
Useful for understanding package configurations, choosing specific versions, and enabling or disabling variants before installation.
Example:
```
spack info python
```

Purpose: Adds a package to a Spack environment.
Usage: spack add <package_name>
Description:
Adds a package to the current Spack environment’s configuration file without installing it.
Allows specifying versions and variants (e.g., spack add <package_name>@<version> +<variant>).
Example:
```
spack add python@3.9.6
```

Purpose: Shows a detailed view of a package’s configuration.
Usage: spack spec <package_name>
Description:
Displays how Spack will interpret a package request, including dependencies, versions, and variants.
Useful for understanding how Spack resolves a package’s specifications before installation.
Example:
```
spack spec python@3.9.6
```

Purpose: Shows a detailed view of a package’s configuration.
Usage: spack spec <package_name>
Description:
Displays how Spack will interpret a package request, including dependencies, versions, and variants.
Useful for understanding how Spack resolves a package’s specifications before installation.
Example:
```
spack spec python@3.9.6
```

Purpose: Ensures all dependencies are fully specified for a Spack environment.
Usage: spack concretize
Description:
Finalizes package versions, variants, and dependencies based on the environment’s specifications, preparing it for installation.
Resolves any ambiguities in the environment configuration to ensure compatibility across packages.
Example:
```
spack concretize
```

Purpose: Installs a package within the Spack environment.
Usage: spack install <package_name>
Description:
Downloads, builds, and installs the specified package, along with its dependencies.
Allows specifying versions and variants (e.g., spack install <package_name>@<version> +<variant>).
Can be used with flags such as --fail-fast to stop on the first error.
Example:
```
spack install gcc@10.2.0 +fortran
```

Purpose: Loads an installed package into the current environment.
Usage: spack load <package_name>
Description:
Modifies environment variables (e.g., PATH, LD_LIBRARY_PATH) to include the specified package.
Useful for making packages available in the shell without permanently adding them.
Allows loading specific versions (e.g., spack load <package_name>@<version>).
Example:
```
spack load python@3.9.6
```