Automatically run certain server commands at certain times

[MilesBHuff]

It would be nice to be able to automatically run certain commands at certain times on the server. While we could look for a plugin to do this, it would be better if we could just pipe commands to the GNU screen that the server is running in; then, we could make any such automations part of cron.

In particular, I'd like the server to auto-restart once a day; and I'd like to refresh the Dynmap once a week.

[MilesBHuff]

I've figured out how to send commands to GNU screen, thanks to StackOverflow:
screen -S $SCREEN_NAME -X stuff "$COMMAND\n"

[MilesBHuff]

@krislamo This is the GitHub issue for what we talked about today (it already existed). ;)

[MilesBHuff]

Link for people to view our current plan: https://docs.google.com/document/d/1E9F2MIuUU_uPq3ZaEpfvTDR__DAz4wq8D5xCKfoO194/edit?usp=sharing

[MilesBHuff]

I should use systemd timers for this, instead of cron.

[MilesBHuff]

I finally implemented this! :D
I did it with cron, not systemd. Perhaps I should revisit that later.
Also, I didn't follow the plan from the Google doc. The most notable deviations are [1] no coordination with the backup server, and [2] the Minecraft server stays online during all of the maintenance, only restarting at the very end.
Anyways, here's the main commit: c24f64b

[MilesBHuff]

I should use systemd timers for this, instead of cron.

New ticket opened for this: #201.