conda env update

Update the current environment based on environment file

Overview

The conda env update command updates an existing conda environment based on an environment definition file. This is useful for adding new packages or updating existing ones while preserving the environment.

Syntax

conda env update [options]

By default, conda env update uses environment.yml in the current directory and updates the currently active environment.

Target Environment Specification

-n, --name · string

Name of environment to update. If not specified, conda will:

1. Use the name from the environment file
2. Fall back to the currently active environment (CONDA_DEFAULT_ENV)

-p, --prefix · string

Full path to environment location (i.e. prefix).

File Options

-f, --file · string · default: "environment.yml"

Environment definition file containing the packages to install or update.

Supported formats:

• YAML environment files (environment.yml)
• Requirements.txt files
• Any format supported by environment specifier plugins

Update Behavior Options

--prune · boolean · default: false

Remove installed packages not defined in environment.yml. This makes the environment match the specification file exactly.

Using --prune will remove any packages not listed in the environment file. This includes packages you may have manually installed.

Environment Specifier Options

--environment-specifier · string

Specify which environment specifier plugin to use for parsing the environment file.

Frozen Environment Options

--override-frozen · boolean

DANGEROUS. Use at your own risk. Ignore protections if the environment is frozen.

Frozen environments are typically protected for a reason. Only use this flag if you understand the implications.

Solver Options

--solver · string

Choose which solver backend to use.

Output and Prompt Options

--json · boolean

Report all output as JSON. Suitable for using conda programmatically.

-v, --verbose · boolean

Can be used multiple times. Once for INFO, twice for DEBUG, three times for TRACE.

-q, --quiet · boolean

Do not display progress bar.

Examples

Update current environment

conda activate myenv
conda env update

Updates the active environment using environment.yml in the current directory.

Update specific environment

conda env update -n myenv -f environment.yml

Updates myenv environment with packages from the specified file.

Update with pruning

conda env update --prune

Updates the environment and removes packages not listed in environment.yml.

Update from specific file

conda env update -f /path/to/environment.yml

Updates using a file from a specific location.

Update from requirements.txt

conda env update -f requirements.txt -n myenv

Updates environment using a pip requirements file.

Update with verbose output

conda env update -v

Shows detailed information during the update process.

Common Use Cases

Adding new dependencies to a project

Update your environment.yml and apply changes:

1. Edit environment.yml:

name: myproject
dependencies:
  - python=3.11
  - numpy
  - pandas  # newly added

2. Update the environment:

conda env update

Synchronizing environments across team members

Team members can update their environments to match the project specification:

git pull  # Get latest environment.yml
conda env update --prune  # Match exactly

Updating package versions

Change version constraints in environment.yml:

dependencies:
  - python=3.11
  - pandas>=2.0  # Updated from pandas>=1.5

conda env update

Adding environment variables

Update environment variables without recreating:

name: myenv
dependencies:
  - python=3.11
variables:
  NEW_VAR: value  # Newly added

conda env update

Selective updates vs full sync

Without --prune (additive):

conda env update
# Adds/updates packages, keeps extra packages

With --prune (exact match):

conda env update --prune
# Makes environment match file exactly

Update Behavior

Without —prune (Default)

• Packages in the file are installed or updated
• Existing packages not in the file are kept
• Dependencies are resolved and may be updated

Example:

Current environment: python=3.11, numpy=1.24, pandas=1.5, matplotlib=3.7

Environment file:

dependencies:
  - python=3.11
  - numpy=1.26
  - pandas=2.0

Result: python=3.11, numpy=1.26, pandas=2.0, matplotlib=3.7 (matplotlib kept)

With —prune

• Packages in the file are installed or updated
• Packages not in the file are removed
• Environment matches the file exactly

Example:

Current environment: python=3.11, numpy=1.24, pandas=1.5, matplotlib=3.7

Environment file:

dependencies:
  - python=3.11
  - numpy=1.26
  - pandas=2.0

Result: python=3.11, numpy=1.26, pandas=2.0 (matplotlib removed)

Differences from conda env create

Feature	conda env create	conda env update
Target	Creates new environment	Updates existing environment
Existing packages	N/A	Preserved by default
—prune flag	N/A	Can remove unlisted packages
Use case	Initial setup	Ongoing maintenance

Troubleshooting

Unable to determine environment

Provide an explicit environment name:

conda env update -n myenv -f environment.yml

Or activate the environment first:

conda activate myenv
conda env update

Environment is frozen

If you get a frozen environment error:

conda env update --override-frozen

Only use this if you’re sure about modifying a frozen environment.

Conflicts after update

If packages conflict after update, try:

1. Use --prune for a clean state:

conda env update --prune

2. Or recreate the environment:

conda env remove -n myenv
conda env create -f environment.yml

File not found

Ensure the file exists:

ls -l environment.yml
conda env update -f ./environment.yml

Best Practices

Use Version Control

Keep environment.yml in version control to track changes and coordinate with team members.

Test Before Pruning

Test conda env update without --prune first to ensure the update works as expected.

Document Changes

Add comments to environment.yml explaining why packages are included or version-pinned.

Regular Updates

Periodically update environments to get security patches and bug fixes.

Related Commands

• conda env create - Create a new environment from file
• conda env export - Export environment to a file
• conda update - Update packages in current environment
• conda install - Install additional packages
• conda env remove - Remove an environment