How to remove an environment variable on GitHub actions?

In GitHub Actions workflows, environment variables can be set in various ways, but deleting them at runtime is not an inherent feature. In other words, once an environment variable is set, it remains available throughout the entire GitHub Actions workflow execution unless explicitly modified or reset via a script during a specific step.

If you need to 'delete' or clear the value of an environment variable in a specific step of the workflow, you can achieve this by running a script within that step, which sets the variable's value to an empty string or directly unsets it. Here are examples of how to achieve this in different shells:

yaml
jobs:
  example_job:
    runs-on: ubuntu-latest
    steps:
      - name: Set environment variable
        run: echo "MY_VAR=myvalue" >> $GITHUB_ENV

      - name: Use environment variable
        run: |
          echo "The value of MY_VAR is $MY_VAR"
          # Assuming we need to use the environment variable here

      - name: Remove environment variable
        run: |
          echo "Removing MY_VAR..."
          echo "MY_VAR=" >> $GITHUB_ENV # Sets the environment variable's value to an empty string

      - name: Check environment variable
        run: |
          if [ -z "${MY_VAR}" ]; then
            echo "MY_VAR is empty."
          else
            echo "MY_VAR still has the value: $MY_VAR"
          fi

In the above example, by executing echo "MY_VAR=" >> $GITHUB_ENV within the step, we set the value of MY_VAR to an empty string, which is generally equivalent to deleting the environment variable. If you want to completely unset an environment variable within a specific shell script, you can use the unset command:

yaml
- name: Unset environment variable
  run: |
    unset MY_VAR
    if [ -z "${MY_VAR}" ]; then
      echo "MY_VAR is unset."
    else
      echo "MY_VAR still has the value: $MY_VAR"
    fi

Note that these changes only affect the current step and subsequent steps. Additionally, if you need to delete or modify environment variables from secrets, this must be done manually in the GitHub repository settings and cannot be achieved through workflow scripts. The general approach to setting environment variables in GitHub Actions is defined through the YAML files under the workflows directory. To delete an environment variable, you can edit the corresponding GitHub Actions workflow configuration file.

The steps to delete environment variables are:

1. Find and edit the Workflow file: First, locate and open the relevant workflow file in the .github/workflows directory of your repository (typically ending with .yml or .yaml). This file defines the execution details of GitHub Actions.

2. Delete the environment variable: Open the workflow file you want to modify, find the section defining environment variables (either the global env field or an env field within a specific job or step), and remove or comment out the corresponding key-value pair.

For example, if you have the following workflow file content:

yaml
name: Example workflow

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      MY_SECRET_TOKEN: ${{ secrets.MY_SECRET_TOKEN }}
      ANOTHER_ENV: some_value
    steps:
    - name: Check out repository code
      uses: actions/checkout@v2
    - name: Run a script
      run: echo "Script that uses environment variables"

To delete the environment variable ANOTHER_ENV, you can remove or comment out the line ANOTHER_ENV: some_value under the env field:

yaml
jobs:
  build:
    runs-on: ubuntu-latest
    env:
      MY_SECRET_TOKEN: ${{ secrets.MY_SECRET_TOKEN }}
      # ANOTHER_ENV: some_value

1. Commit and push changes: After editing, commit the changes to your repository and push them to the remote repository. Include a descriptive commit message, such as Remove ANOTHER_ENV variable from GitHub Actions workflow.

2. Verify workflow execution: After committing and pushing, GitHub Actions will automatically trigger the workflow. Check the workflow run to confirm that deleting the variable does not disrupt normal operation.

If you are discussing the deletion of environment variables stored in GitHub Secrets, you must manually delete the corresponding secret through the GitHub repository settings. This is typically done by repository administrators via the GitHub web interface:

1. Click the Settings tab in your repository.
2. Navigate to the Secrets section in the left sidebar.
3. Click the Update or Delete button next to the secret you want to remove.
4. Confirm the deletion if prompted; the secret will be removed.

In summary, these are the methods to delete environment variables in GitHub Actions. Note that if other parts of the workflow depend on the deleted variable, it may cause workflow failures. Therefore, deletion should be performed cautiously to minimize disruption.