Mastering Environment Variables in JavaScript, Python, Java, PHP, C#, C++, C, Perl, and Operating systems
Tags: programming, javascript, python, php
Published: 2022-12-18 16:39:16

## INTRODUCTION
Discover the game changer ‘ENVIRONMENT VARIABLES’ and transform the way you work. From secure storage of secrets to dynamic configuration, these hidden gems have the power to streamline your workflow and take your productivity to the next level.

## WHAT ARE ENVIRONMENT VARIABLES
Environment variables are variables that are stored in the operating system and can be used by processes to configure their behavior. These variables can be set at the system level or at the user level, and they can store a wide range of information, such as paths to directories or executables, database connection strings, or API keys.

In JavaScript, you can access environment variables in the `process.env` object. For example, to access an environment variable called `API_KEY`, you can use the following code:

```
const apiKey = process.env.API_KEY;
```

You can also set environment variables in JavaScript by using the process.env object. However, keep in mind that these changes will only be available to the current process and will not be persisted across restarts.

```
process.env.API_KEY = 'my-api-key';
```

## USE CASES
It is a good practice to store sensitive information, such as passwords and API keys, as environment variables rather than hardcoding them into your code. This helps to protect this information and makes it easier to manage. For example, you might use environment variables to store API keys that are needed to access external services. This way, you can easily change the keys without having to update your code.

In addition to storing sensitive information, environment variables can also be used to customize the behavior of your applications. For example, you might use environment variables to store the URL of a database, so that you can easily switch between different environments (e.g. production, staging, development) without having to update your code.
Overall, environment variables are a powerful tool for configuring and customizing the behavior of your applications. By using them, you can make your code more flexible and easier to manage, while also improving security.

## WAYS TO CREATE ENVIRONMENT VARIABLE IN VARIOUS PROGRAMMING LANGUAGES AND HOW TO ACCESS THEM

**Python**
In Python, you can set environment variables using the `os` module:
```
import os
os.environ['foo'] = 'bar’
```
You can access it  this way

```
foo = os.environ['FOO']
```

**JavaScript**

As earlier stated you can set environment variables in javascript using the `process.env` object:
``` 
process.env.API_KEY = 'my-api-key';
```
You can access it this way
```
const foo = process.env.FOO;
```

**C#**
In C#, you can set environment variables using the `System.Environment` class:
```
System.Environment.SetEnvironmentVariable(‘Foo’,’my-api-key’)
```
You can access it this way
```
string foo = System.Environment.GetEnvironmentVariable("FOO");
```

**Java**
In Java, you can set environment variables using the `System.setenv` method:
```
System.setenv("FOO", "BAR");
```
You can access it this way
```
String foo = System.getenv("FOO");
```

**C++**
In C++, you can set environment variables using the `std::setenv` function:
```
#include <stdlib.h>
 std::setenv("FOO", "BAR", 1);
```
You can access it this way
```
std::string foo = std::getenv("FOO");
```
**C**
In C, you can set environment variables using the `setenv` function:
```
#include <stdlib.h>
setenv("FOO", "BAR", 1);
```
You can access it this way
```
char* foo = getenv("FOO");
```
**Ruby**
In Ruby, you can set environment variables using the `ENV` hash:
```
ENV['FOO'] = 'BAR'
```

You can access it this way
```
foo = ENV['FOO']
```
**PHP**
In PHP, you can set environment variables using the `putenv` function:
```
putenv("FOO=BAR");
```

You can access it this way
```
$foo = getenv('FOO');
```

**Perl**
In Perl, you can set environment variables using the `%ENV` hash:
```
$ENV{'FOO'} = 'BAR';
```
You can access it this way
```
$foo = $ENV{'FOO'};
```

Notice how some of them were stored in variables for easy accessibility.

Note that environment variables are often case-sensitive, so be sure to use the correct case when setting them. Also, keep in mind that the scope and persistence of environment variables will depend on how and where they are set. Some environment variables are set for the current session or process only, while others are set for the system or for a specific user and persist across sessions.

##The .env extension
The ".env" file extension is often used for configuring files that contain environment variables or other sensitive information. These files are commonly used in web development to store configuration values such as database credentials, API keys, and other secrets.

The ".env" file is typically placed in the root directory of a project and is used to set environment variables for the application. The file is usually ignored by version control systems, so that the sensitive information it contains is not committed to the repository,
To use the environment variables in a ".env" file, you can use a library or framework that supports loading environment variables from the file. For example, in a Node.js application, you can use the `dotenv` package to load environment variables from a ".env" file into the `process.env` object:
In other languages, you can use similar libraries or frameworks to load environment variables from a ".env" file.

It's important to keep in mind that the ".env" file should not be committed to version control and should be treated as sensitive information. It's a good practice to store the ".env" file in a secure location and to protect it with appropriate permissions.

##HOW TO SET ENVIRONMENT VARIABLES IN WINDOWS , MAC , LINUX AND UBUNTU 

On Windows, you can set environment variables for the system or for a specific user using the "Environment Variables" button on the "Advanced" tab of the "System Properties" window. To open this window, you can go to the Start menu and search for "Environment Variables" or go to Control <u>Panel > System and Security > System > Advanced system settings.</u>

To set environment variables using the command line on Windows, you can use the "setx" command. For example, to set the environment variable "FOO" to "BAR" for the current user, you can use the following command:

```
setx FOO "BAR"
```
On macOS and Linux, you can set environment variables for the system or for the current user using a configuration file. The configuration file to use and the exact syntax will depend on the shell you are using.

For example, in the bash shell, you can set environment variables for the current user in the ".bashrc" file in the user's home directory. To set the environment variable "FOO" to "BAR" for the current user in the bash shell, you can add the following line to the ".bashrc" file:
```
export FOO="BAR"
```
To set environment variables for the system in the bash shell on macOS and Linux, you can add the same line to the <u>"/etc/environment" </u>file.

On Ubuntu, you can also use the "export" command to set environment variables for the current terminal session. For example, to set the environment variable "FOO" to "BAR" for the current terminal session, you can use the following command:
```
export FOO="BAR"
```

To make the environment variable persist across terminal sessions, you can add the same line to the ".bashrc" file in the user's home directory, as described above.

To access environment variables in a command shell, you can use the `echo` command or the `printenv` command, followed by the name of the environment variable. For example, to access the value of the "FOO" environment variable in the bash shell, you can use the following command:

To access environment variables in a command shell, you can use the `echo` command or the `printenv` command, followed by the name of the environment variable. For example, to access the value of the "FOO" environment variable in the bash shell, you can use the following command:
```
echo $FOO
```


You can also access environment variables using the % syntax in the command prompt on Windows:

```
echo %FOO%
```

##Conclusion
Environment variables are easy to use, and they give you a better way to structure your app, You can now use them like a pro.

_I am Abraham Covenant, and I am a full-stack developer with a passion for building beautiful and functional web applications. I have a strong understanding of HTML, CSS, and JavaScript, as well as experience with popular CSS frameworks such as Tailwind CSS and Bootstrap5. I am also proficient in React,Solidity and PHP and I enjoy using these technologies to create scalable and responsive front-end interfaces._

_I am always looking for ways to improve and expand my skills, and I am eager to learn new technologies and techniques to stay at the forefront of web development._

_If you are looking for a full-stack developer , I would love to speak with you about how I can be of help. Thank you_
My email for personal [discussions](abrahamcovenant2004@gmail.com)