> There's a single implementation as far as I know
That's exactly what I mean.
Systemd itself, including timers, is deeply coupled with the Linux API, and cannot be (easily) ported on any other system. Cron, on the other hand, exists on almost every UNIX-like system.
systemd is is many things, but obvious and accessible is not one of them. It has a lot of power and flexibility, but the trade off is a lot of complexity. Just look at the unit configuration file:
I have no idea from that documentation how I'd run something every hour. I guess I have to create a new unit file, and use the OnCalendar stanza? But what do I set it to? I'm directed to this page:
I started my career as a Unix SA over 25 years ago and have worked with a lot of different Unix-flavored operating systems: SunOS/Solaris, HP/UX, FreeBSD, Linux (Slackware, RedHat, Debian), macOS/OS X, AIX. I'm familiar with all their different variations of init.
All of them are esoteric in one way or another. Some of them have their behavior right out in the open where it's easy to see (inittab and rc scripts). Others hide away massive complexity (launchd and systemd) and require extensive documentation to understand.
I appreciate all the power that systemd provides. It gets a lot of things right. But in terms of complexity, it's almost an operating system unto itself.
I'm not quite sure why you felt pressed to write this long-winded response to something I didn't write. I never said that systemd is easy. I said that if someone is running *BSD, today, in 2024, they'll cope with cron's syntax.
I'll still reply to one part:
> Oh, I see I can use "hourly" but it turns out that's syntactic sugar for:
> *-*-* *:00:00
>Is that really any easier than the cron equivalent?
> 0 * * * *
...Yes? Ask someone who's not familiar either with cron or systemd to guess what each one mean, with the context that it's supposed to be something related to dates and times. If you're vaguely familiar with how dates are usually written down, and that a star is a wildcard, you can immediately guess that the first one means "any year, any month, any day, any hour, at the first minute, first second". The cron one? It's anyone's guess.
Hah, that's fair. I inferred from your comment the corollary that systemd is not arcane, and thought "oh, it's just arcane differently," hence my long-winded reply.
You can argue that no other system matters (which I strongly disagree with for reasons I don't want to get into right now), but that doesn't make systemd timers any more portable.
I’d argue that the degree of portability implied by the term is very much context dependent. “Portable between Linux systems” is a perfectly valid use of the term, imo.
Do you take portable to mean a program that can run on every processor arch and OS available?
> Do you take portable to mean a program that can run on every processor arch and OS available?
The definition of the word "portable" is not the point of this comment thread (although if you want to hear my definition, see the reply to a sibling comment).
Let's take the context into account:
> hashworks:
While I support systemd timers over cron, AFAIK cron has stuff like @hourly.
> caiusdurling:
Some cron implementations do, it's not portable.
> bheadmaster:
Neither are systemd timers. I don't think there's a single system out there implementing the systemd timer interface.
User caiusdurling said @hourly is not portable between cron implementations as a way to discredit hashworks' argument about cron having @hourly.
However, that's a disingenious argument, because systemd timers aren't any more portable than cron implementations that use @hourly - in fact, there isn't a single system out there implementing the systemd timer interface except systemd.
Portable means easy to make it work while changing the underlying system or its implementation details - where the underlying system refers to architecture, OS, API or any other dependencies needed to run the program.
In context of systemd, systemd isn't portable because it highly depends on Linux API and thus cannot be ported on any other UNIX-like (or unlike) OS.
In context of systemd timers, systemd timers aren't portable because there isn't as single alternative implementation that can interpret systemd timer unit files.
