Daily Quests with systemd

I always loved how games give you daily quests to keep you engaged. I wanted the same thing for coding practice apparently, so I created a simple system using systemd timers and a bash script that picks a random challenge and language combination every day.

The Setup

The system consists of three components:

• A systemd service unit that executes the challenge picker
• A systemd timer that triggers it daily at 8 AM
• A bash script that deterministically selects challenges based on the date

Service Configuration

~/.config/systemd/user/daily-war.service,

[Unit]
Description=Generate daily coding war

[Service]
Type=oneshot
ExecStart=/home/safal726/.local/bin/daily-war.sh

Timer Configuration

~/.config/systemd/user/daily-war.timer

[Unit]
Description=Daily War Timer

[Timer]
OnCalendar=*-*-* 08:00:00
Persistent=true

[Install]
WantedBy=timers.target

The Challenge Picker Script

#!/usr/bin/env bash
set -e

SRC="$HOME/.cache/safalQuick/coding_challenges.json"
OUT="$HOME/.cache/safalQuick/todaywarpick.json"

SEED=$(date +%Y%m%d)
TODAY=$(date -I)

if [[ -f "$OUT" ]] && jq -e --arg d "$TODAY" '.date == $d' "$OUT" >/dev/null 2>&1; then
  exit 0
fi

jq --arg seed "$SEED" --arg date "$TODAY" '
  def pick(arr; mul):
    arr[(($seed | tonumber) * mul) % (arr | length)];

  {
    date: $date,
    challenge: pick(.challenges; 73),
    language: pick(.languages; 97)
  }
' "$SRC" >"$OUT"

How It Works

• Generates a numeric seed from today’s date (e.g., 20251229)
• Creates an ISO-format date string for tracking
• Uses the date seed multiplied by a prime number [73 for challenge, 97 for language]
• Creates a JSON object with today’s date, selected challenge, and selected language
• Writes to todaywarpick.json for consumption by other tools

systemctl --user enable daily-war.timer
systemctl --user start daily-war.timer

I have implemented the UI part here…