I found the systemd time spec syntax you referenced to be logical and well thought out.

Cron syntax is simpler for the easy cases because cron tries to do less. It ignores years and seconds entirely, and doesn't try to adhere roughly to ISO8601 ordering and field separators, instead using space universally for field separation and euro-style least-to-most significant field ordering. I like ISO8601, so I get along with systemd's style better, despite it introducing slightly more cognitive load.

The only thing that threw me for a loop and seems like "special magic" was

> "Mon *-05~07/1" means "the last Monday in May."

But good luck doing that in one line in cron.

Some cron-style libraries seem to support L/W/# for last / nearest-weekday / nth of month, but I don't know if any system crons do. (cronie? dcron? I don't think so. fcron? bcron? I don't see it there either.) '#' is syntactic sugar for DOW + 7-day range, while L is covered by the above quoted syntax.

If your cron has that kind of syntax, then for a case like "weekday closest to 1st of month", "W" is more convenient than writing 3 systemd timer rules to cover the three cases (weekday day 1, monday day 2, friday last day of month), but that's a big if. Generally you'd have to write 3 rules in cron anyway.

To be honest it looks rather easy to digest? I can sort of guess the meaning without documentation.

For cron, despite years of looking at it, I can never remember what those numbers mean and I need to Google almost every time.

If you know the syntax, it's still actually rather trivial. Still easier to read than advanced cron magic.

> In cron, you basically have to either use your configuration management to generate those times, or have a random delay script running before the command

Nope. From crontab(5)

  The  RANDOM_DELAY variable allows delaying job startups by random amount
  of minutes with upper limit specified by the variable. The random  scal‐
  ing  factor  is  determined during the cron daemon startup so it remains
  constant for the whole run time of the daemon. 

That's from my cronie install, but it looks like this has been a feature of some crons for at least a decade. (Notice that the post date of [0] is in 2016.) Given that cronie is based on vixie-cron, and I think I was was using vixie-cron in 2002, I bet it's been a thing for at least twenty years.

[0] <https://stackoverflow.com/a/34815984>

`* 1 * * * sleep $(( $(od -N1 -tuC -An /dev/urandom) \% 45 ))m ; <your command here>`

So the `OnCalendar` stanza is the same as a Cron job; without the helpful comments of the ordering? And that is considered _easier_??

Just use Cron. It does one thing and does it well.

I, er, what? It's... the same as cron? I'm confused now. It's not exactly the same, I guess?