Monitoring Files and Folders with launchd: WatchPaths in Practice

Thu, 26 Mar 2026 18:56:00 +0000

In the previous post about launchd, scheduling worked by time: StartCalendarInterval defined “every day at 7 AM” and the system took care of the rest, including recovering missed executions when the Mac was asleep. For periodic tasks like sending a daily briefing or running a maintenance script, that model works perfectly — it is the functional equivalent of cron, but integrated into the macOS lifecycle.

But not every automation makes sense tied to a clock. Some tasks only need to happen when something changes. A backup that runs every hour is wasting 23 executions per day if the database was only modified once. An image conversion that runs every 5 minutes has nothing to convert most of the time, and when it finally does, up to 5 minutes have passed since the file appeared. The time-based model works, but it is polling disguised as scheduling — and polling is almost always the least elegant solution to any synchronization problem.

Scheduling Tasks on macOS with launchd: No cron, No Workarounds

Mon, 23 Mar 2026 21:29:00 +0000

In the previous post I showed how systemd timers replace cron on Debian and Ubuntu servers with concrete advantages: integrated logging, missed execution recovery, declarative dependencies, and resource control. The logic is compelling and the migration is straightforward — as long as you are on a system running systemd. But if your daily routine includes a Mac, it is a different story.

macOS has its own scheduling system, predating systemd and built on a different philosophy. It is called launchd, it has been around since Mac OS X Tiger in 2005, and it is responsible for practically everything that runs in the background on the system — from internal Apple services to that Spotify updater you never asked to install. Despite being the official and recommended way to schedule tasks on a Mac, launchd lives in a kind of blind spot: people coming from Linux tend to reach for cron out of reflex, and Mac users without a sysadmin background do not even know the option exists.

Launchd on /var/log/janio

Monitoring Files and Folders with launchd: WatchPaths in Practice

Scheduling Tasks on macOS with launchd: No cron, No Workarounds