Loading .env files with no dependencies

Guy Waldman

July 26, 2024 (1 year 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

#Problem

#Solution

#References

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