5 October 2025
Tech Tips

Automate a task with scripting

Here’s a practical, step-by-step guide to automate a task with scripting. I’ll include a generic workflow plus concrete examples in Python and Bash, plus how to schedule the automation.

  1. Define the task clearly
  • What needs to happen, and when?
  • Inputs: where do you get data or files from?
  • Outputs: where should results go, and in what format?
  • Success criteria: how do you know it worked?
  • Constraints: error handling, rate limits, authentication, platform (Windows/Linux/macOS).
  1. Choose a scripting language
  • Quick, cross-platform: Python (great for API calls, files, data processing).
  • Simple system tasks on Unix-like systems: Bash shell script.
  • Windows-specific tasks: PowerShell.
  • If you’re already using a tool (e.g., Node, Ruby), you can script in that language too.
  1. Set up your environment
  • Install the language runtime (Python, etc.).
  • Create a project directory (e.g., automate-task/).
  • Create a virtual environment (optional but recommended for Python):
    • python3 -m venv venv
    • source venv/bin/activate (bash/zsh) or venv\Scripts\activate (Windows)
  • Install any dependencies:
    • Python: pip install requests # etc.
  1. Design the script’s behavior
  • Make it idempotent when possible (running twice shouldn’t duplicate work or break things).
  • Add logging to capture what happened.
  • Add error handling to manage failures gracefully.
  • Use configuration (env vars or a config file) instead of hard-coding values.
  1. Create the script
  • Break tasks into functions or steps.
  • Keep inputs/outputs explicit (paths, filenames).
  • Include a main entry point to allow running as a script.

Example 1: Python – automate downloading a daily report from a URL and save to a folder What it does: fetches a file from a URL that changes daily, saves with a date-stamped name, logs success/failure.

Code (save as automate_download.py): import os import requests from datetime import datetime

Config

DOWNLOAD_URL = os.environ.get(“DOWNLOAD_URL”, “https://example.com/daily-report”) DEST_DIR = os.environ.get(“DEST_DIR”, “./reports”) TIMEOUT = 20 # seconds

def ensure_dir(path): os.makedirs(path, exist_ok=True)

def get_today_filename(): date_str = datetime.utcnow().strftime(“%Y-%m-%d”) return f”daily_report_{date_str}.pdf” # adjust extension as needed

def download_file(url, dest_path): with requests.get(url, stream=True, timeout=TIMEOUT) as r: r.raise_for_status() with open(dest_path, “wb”) as f: for chunk in r.iter_content(chunk_size=8192): if chunk: f.write(chunk)

def main(): ensure_dir(DEST_DIR) filename = get_today_filename() dest_path = os.path.join(DEST_DIR, filename) if os.path.exists(dest_path): print(f”{dest_path} already exists. Skipping download.”) return try: print(f”Downloading {DOWNLOAD_URL} to {dest_path} …”) download_file(DOWNLOAD_URL, dest_path) print(“Download completed.”) except Exception as e: print(f”ERROR: {e}”)

if name == “main“: main()

How to run:

  • Set any needed environment variables:
    • export DOWNLOAD_URL=”https://example.com/daily-report”
    • export DEST_DIR=”/path/to/reports”
  • Run: python automate_download.py
  • For logs, you can redirect: python automate_download.py >> automate.log 2>&1

Example 2: Bash – rotate a folder of log files daily (move old logs to archive) What it does: moves log files older than 7 days to an archive directory with a date stamp.

Script (save as rotate_logs.sh): #!/usr/bin/env bash set -euo pipefail

LOG_DIR=”${1:-./logs}” ARCHIVE_DIR=”${2:-./logs_archive}” DAYS=”${3:-7}”

mkdir -p “$ARCHIVE_DIR” find “$LOG_DIR” -type f -name “.log” -mtime +”$DAYS” -print0 | while IFS= read -r -d ” f; do base=$(basename “$f”) date_tag=$(date +%Y%m%d) dest=”$ARCHIVE_DIR/${base%.}_$date_tag.${base##*.}” mv “$f” “$dest” echo “Moved $f -> $dest” done

Make it executable:

  • chmod +x rotate_logs.sh

Run:

  • ./rotate_logs.sh /path/to/logs /path/to/logs_archive 7
  1. Add error handling and logging
  • For Python: use try/except blocks; log to a file with timestamps.
  • For Bash: check exit codes after commands; append to a log file.
  1. Test the script
  • Run in a dry/run-safe mode if possible.
  • Test with sample data, different edge cases.
  • Verify outputs and logs match expectations.
  1. Schedule the task
  • Linux/macOS (cron):
    • Run crontab -e and add a line, e.g.: 0 6 * * * /usr/bin/python3 /path/to/automate_download.py >> /path/to/automate.log 2>&1
    • This runs daily at 06:00.
  • Windows (Task Scheduler):
    • Create Basic Task, set trigger (daily), action: start a program (python.exe) with arguments: “C:\path\to\script.py”.
  • Docker/CI: If your task needs to run in a container or as part of CI, wrap the script in a container run and schedule accordingly.
  1. Monitor and maintain
  • Check logs regularly for failures.
  • Add alerting (email, Slack) on failures if needed.
  • Update credentials securely (use environment variables or a secrets manager, not hard-coded).
  1. Quick troubleshooting tips
  • If a script fails, run it in verbose mode or with -x (for Bash) or logging enabled to see where it breaks.
  • Ensure permissions allow reading/writing files and network access if downloading.
  • Use absolute paths to avoid working-directory issues in scheduled tasks.
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