Honestly, I'm finding Apple's launchctl and plist (XML?) usage to be somewhat confusing and overkill. Using Terminal, I just wanna say hey, macOS, start program.app at boot! or hey, macOS, start my /path/to/shell.sh at boot!
How can I add a boot item --remotely via Terminal/SSH/Netcat/command line/shell?
sh-3.2# system_profiler SPSoftwareDataType
Software:
System Software Overview:
System Version: macOS 10.13.4 (17E199)
Kernel Version: Darwin 17.5.0
Boot Volume: lily
Boot Mode: Normal
Computer Name: lily’s MacBook Air
User Name: System Administrator (root)
Secure Virtual Memory: Enabled
System Integrity Protection: Enabled
Time since boot: 2:03
launchd
. Here's another answer on how to run something at boot (no interval) – Allan May 18 '18 at 11:32