Loading Environment Variables from .env Files

#!/bin/bash

# Path to your .env file relative to the script
ENV_FILE=".env"

# Check if the .env file exists
if [ -f "$ENV_FILE" ]; then
  echo "Loading environment variables from $ENV_FILE..."
  # Read each line, filter out comments and empty lines, and export variables
  # The 'eval' command is used carefully here as the source of variables is controlled
  # An alternative without eval is 'export $(grep -v '^#' "$ENV_FILE" | xargs)'
  # but using a loop is safer for complex values and allows for feedback.
  while IFS='=' read -r key value; do
    # Skip empty lines and comments
    [[ -z "$key" ]] || [[ "${key:0:1}" == "#" ]] && continue

    # Remove potential quotes from value (simple case)
    value=$(echo "$value" | sed -e 's/^"//' -e 's/"$//')

    # Export the variable
    export "$key"="$value"
    echo "  Exported: $key"
  done < "$ENV_FILE"
else
  echo "Warning: .env file not found at $ENV_FILE. No environment variables loaded."
fi

# Example of using loaded variables
echo "
--- Using loaded variables ---"
if [ -n "$DB_HOST" ]; then
  echo "Database Host: $DB_HOST"
fi

if [ -n "$API_KEY" ]; then
  echo "API Key (first 5 chars): ${API_KEY:0:5}..."
fi

if [ -n "$APP_ENV" ]; then
  echo "Application Environment: $APP_ENV"
fi

# To demonstrate, create a .env file like this in the same directory:
# DB_HOST=localhost
# DB_PORT=5432
# API_KEY="your_secret_api_key_12345"
# APP_ENV=development
# # This is a comment