Loading .env files with no dependencies

Guy Waldman

July 26, 2024 (2 years ago)

Problem

You have environment variables that you want to use in your project, and don't want to manually export them (and expose them in your shell history).
So you create a local (git ignoreD!) .env file that you wish to load into your BASH or ZSH shell session, that looks like so:

MY_SECRET="super-secret-value"
MY_OTHER_SECRET="other-secret-value"

You want a simple script which will load these variables into your shell session, and you don't want to install any dependencies to do this (e.g., dotenv-cli.

Solution

# Loads environment variables from a file into the current shell.
# Usage: dotenv <env_file_path>
function dotenv {
	env_file_path="$1"

	# Bail out if the file doesn't exist.
	if [ ! -f "$env_file_path" ]; then
		echo "Error: File '$env_file_path' does not exist." >&2
		return 1
	fi

	echo "Loading environment variables from '$env_file_path...'"
	# `sllexport`: Each variable or function that is created or modified is given the export attribute and marked for export to the environment of subsequent commands.
	set -o allexport
	source <(sed -e "s/\r//" -e '/^#/d;/^\s*$/d' -e "s/'/'\\\''/g" -e "s/=\(.*\)/=\"\1\"/g" "${env_file_path}")
	set +o allexport

	# Display the environment variables that were loaded.
	env_vars=$(cat "$env_file_path" | grep -E '^[A-Z0-9_]+\s*=' | cut -d = -f 1 | tr '\n' ' ')
	env_vars=($(echo $env_vars))
	echo "Environment variables loaded from '$env_file_path': $(join_by ', ' $env_vars)"
}

References

https://gist.github.com/mihow/9c7f559807069a03e302605691f85572?permalink_comment_id=4287253#gistcomment-4287253

Loading .env files with no dependencies

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