Introduction to with-env

The with-env command is a powerful tool that allows developers to temporarily set environment variables for the execution of commands. This capability can be immensely useful in various scenarios, such as testing, CI/CD pipelines, and ensuring scripts run with the correct context. In this guide, we will explore a comprehensive list of with-env APIs along with practical code snippets.

Basic Usage

To set an environment variable for a single command:

with-env VAR_NAME=value command

Multiple Variables

You can set multiple environment variables at once:

with-env VAR1=value1 VAR2=value2 command

Usage in Scripts

with-env can be particularly useful in scripts. For example, setting variables for a build process:

 #!/bin/sh with-env BUILD_ENV=production API_KEY=abcdef123456 ./build.sh 

Persisting Variables

Persisting environment variables across multiple commands within a script can be done as follows:

 #!/bin/sh export VAR1=value1 export VAR2=value2 with-env VAR1=$VAR1 VAR2=$VAR2 \\
        command1 && \\
        command2

Integrating with Docker

When working with Docker, with-env can streamline the process of setting environment variables:

 with-env DB_HOST=localhost DB_PORT=5432 \\
        docker run -e DB_HOST -e DB_PORT my-docker-image

CI/CD Pipelines

Using with-env in CI/CD pipelines can ensure that your scripts run with the appropriate context:

 stages:
  - test
test:
  stage: test
  script:
    - with-env NODE_ENV=test npm test

Practical Application Example

Let’s put together a sample application code that leverages with-env for setting environment variables and running the application:

 #!/bin/sh echo "Starting application with environment variables..." with-env NODE_ENV=production API_URL=https://api.example.com \\
        node app.js

This script initializes the application with production settings by temporarily setting the NODE_ENV and API_URL variables just for the execution of node app.js.

With these with-env commands and use cases, you can significantly enhance the flexibility and reliability of your scripting workflows.

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