Shell how to set environment variables from .env file

Question

Let's say I have .env file contains lines like below:

USERNAME=ABC PASSWORD=PASS 

Unlike the normal ones have export prefix so I cannot source the file directly.

What's the easiest way to create a shell script that loads content from .env file and set them as environment variables?

Answer 1

If your lines are valid, trusted shell but for the export command

This requires appropriate shell quoting. It's thus appropriate if you would have a line like foo='bar baz', but not if that same line would be written foo=bar baz

set -a # automatically export all variables source .env set +a 

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If your lines are not valid shell

The below reads key/value pairs, and does not expect or honor shell quoting.

while IFS== read -r key value; do   printf -v "$key" %s "$value" && export "$key" done 

Answer 2

This will export everything in .env:

export $(xargs <.env) 

Edit: this requires the environment values to not have whitespace. If this does not match your use case you can use the solution provided by Charles

Edit2: I recommend adding a function to your profile for this in any case so that you don't have to remember the details of set -a or how xargs works.