Load .env File into Current Shell

#!/bin/bash
# Usage: source load_env.sh .env

ENV_FILE=${1:-.env}

if [[ -f "$ENV_FILE" ]]; then
  echo "Loading environment variables from $ENV_FILE..."
  while IFS= read -r line; do
    # Skip comments and empty lines
    [[ "$line" =~ ^#.* ]] || [[ -z "$line" ]] && continue

    # Export key=value pairs
    export "$line"
  done < "$ENV_FILE"
  echo "Environment variables loaded."
else
  echo "Error: .env file not found at $ENV_FILE" >&2
  exit 1
fi

How it works: This script reads a specified `.env` file line by line. It skips comment lines (starting with `#`) and empty lines. For every valid `KEY=VALUE` line, it uses the `export` command to make that variable available in the current shell session. This is extremely useful for managing secrets and configuration without hardcoding them directly into scripts or source code. To use, you must `source` the script (e.g., `source load_env.sh`).