conda compare

Compare packages between conda environments

The conda compare command compares the packages installed in a conda environment with the packages specified in an environment file. This is useful for verifying that an environment matches its specification.

Syntax

conda compare [options] FILE

Arguments

FILE

Path to the environment file that is to be compared against. Can be a local file path or a URL.

conda compare environment.yml
conda compare /path/to/environment.yml
conda compare https://example.com/environment.yml

Options

-n, --name NAME

Name of the environment to compare.

conda compare -n myenv environment.yml

-p, --prefix PREFIX

Full path to the environment prefix to compare.

conda compare -p /path/to/env environment.yml

--json

Report all output as JSON. Suitable for programmatic use.

conda compare --json environment.yml

Output

The command returns:

• Exit code 0: All packages in the specification file are present in the environment with matching version and build string
• Exit code 1: One or more packages are missing or have mismatched versions

Success Output

Success. All the packages in the specification file are present in the environment with matching version and build string.

Error Output

When packages don’t match, the output shows:

• Missing packages: <package_name> not found
• Mismatched packages: <package_name> found but mismatch. Specification pkg: <spec>, Running pkg: <installed>

Common Use Cases

Compare current environment with specification

Compare packages in the current environment with an environment.yml file:

conda compare environment.yml

Compare named environment with specification

Compare a specific environment:

conda compare -n myenv environment.yml

Compare environment with remote specification

Fetch and compare against a remote environment file:

conda compare https://raw.githubusercontent.com/user/repo/main/environment.yml

Use in CI/CD pipelines

Verify that an environment matches its specification:

# Exit with error if environment doesn't match
conda compare environment.yml || exit 1

Get JSON output for automation

conda compare --json environment.yml > comparison_result.json

How It Works

The conda compare command:

1. Reads the environment file (supports various formats via plugins)
2. Extracts the list of requested packages from the specification
3. Gets the list of installed packages in the target environment
4. Compares each package from the specification against installed packages
5. Checks that:
   • The package exists in the environment
   • The version matches the specification (if specified)
   • The build string matches (if specified)

The comparison uses conda’s MatchSpec system, which supports flexible version specifications like >=1.0, 1.*, etc.

Environment File Formats

The command supports different environment file formats through conda’s plugin system, including:

• environment.yml (conda format)
• requirements.txt (pip format)
• Other formats via installed plugins

Example: Complete Workflow

Create environment from file

# Create environment from specification
conda env create -f environment.yml -n myenv

Verify environment matches specification

# Compare to verify installation
conda compare -n myenv environment.yml

Handle mismatches

# Update environment if comparison fails
if ! conda compare -n myenv environment.yml; then
    echo "Environment doesn't match specification, updating..."
    conda env update -n myenv -f environment.yml
fi

Use Cases

• CI/CD validation: Ensure environments in production match specifications
• Debugging: Identify package version mismatches
• Documentation: Verify environment documentation is up-to-date
• Reproducibility: Confirm environments can be reproduced from files
• Compliance: Check that environments meet specific requirements

The conda compare command checks packages specified in the environment file. It does not check for extra packages that may be installed but not specified in the file.