34

I am on Ubuntu 12.04 and I'm just learning about environment variables. I am trying to read a custom variable from within my application but it always shows up as undefined. Here is the code of my test app:

// app.js

console.log('Value: ' + process.env.NODE_ENV);

If I run the following commands you will see that the variable has a value:

$ NODE_ENV=production
$ echo $NODE_ENV
production

I can echo $NODE_ENV all day and it will continue to show me "production", but when I do process.env.NODE_ENV in my Node application it always displays "undefined".

$ node app.js
Value: undefined

Here is the odd part though, if I display another environment variable that I know already exists, say process.env.PATH, then it works.

$ node app.js
Value: /usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

Another quirk is that the command printenv list doesn't appear to contain my custom variable NODE_ENV despite the fact that echo $NODE_ENV shows me the correct value. printenv NODE_ENV shows nothing as well, but printenv PATH shows the proper value just as it did when I accessed PATH in my node application.

Improve this question
1

6 Answers 6

Reset to default
38

You need to export shell variables in order to make them available to processes you execute in your shell.

Compare the output of this command:

FOO=bar; bash -c 'echo $FOO'

with the output of this:

export FOO=bar; bash -c 'echo $FOO'
Improve this answer
Sign up to request clarification or add additional context in comments.

1 Comment

The strange this is that even if I can see variable value using echo $FOO I can't see it using process.env.FOO anyway...
17

I found my way here from something really silly.

I had just added the new exported variables, but my node process still wasn't seeing them. Then I realized it wasn't enough to restart the node process—I had to open a new terminal (ie. bash instance) too. Once I did this, it worked fine :)

(this answer is relevant for when you're exporting the variables from a file, rather than setting them in the current shell instance)

Improve this answer

3 Comments

Thank you, it's working! I got really frustrated why it was 'undefined', all I had to do was exit bash instance and open a new one.
how do you do that? aren't these variables just set in the current shell instance? if you close the current shell and open a new one, wouldn't these variables be lost anyway?
In my case, I even had to restart Visual Studio Code. Killing and restarting the integrated terminal wasn't enough
1

If you are using dotenv make sure to configure before you access the variables in your environment. The order of your code is mattered in js.

Improve this answer

Comments

0

You might want to consider using a library for managing app configuration.

For example nconf helps manage configuration through

  • command line argumets
  • environment variables
  • files
  • etc..

And looking at the source is a nice way to learn https://github.com/flatiron/nconf

Improve this answer

Comments

0

Found my way here from something really silly as well ! I was running my server file from a "src" folder inside my main project directory and so had my .env inside the "src" folder itself (from where my server was running). Once I put the .env in my main project directory, it worked for me. Make sure that your '.env' is in the main directory and not inside "src" folder.

Improve this answer

Comments

-2

Restart your bash (source ~/.bashrc). This will take into account your system environment.

Improve this answer

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.