Update README.md

Arun-Rocker · web-flow · commit 4bf4ebdff713 · 2025-05-04T20:21:14.000+05:30
diff --git a/Day-05/README.md b/Day-05/README.md
@@ -5,13 +5,21 @@ Here's a comprehensive guide to working with environment variables in Python.
 
 using below command we should export env variable to linux/mac
 ```
+# Add to ~/.bashrc, ~/.zshrc, or ~/.profile
+export API_KEY="your_api_key_here"
 export DB_HOST="localhost"
 ```
 
 In the code we call env variable by using `os.getenv`
 ```
 import os
 
-## ** Simple get with optional default **
-api_key = os.getenv('API_KEY', 'default-key')
+# Method 1: os.environ (raises KeyError if missing)
+api_key = os.environ['API_KEY']
+
+# Method 2: os.getenv() (safer, returns None if missing)
+db_host = os.getenv('DB_HOST')
+
+# Method 3: With default value
+db_port = os.getenv('DB_PORT', '5432')  # Default to 5432 if not set
 ```
