Tell me you’ve never used PHP without telling me you’ve never used PHP.
It’s known for giving a complete stack trace, it’s nearest neighbours and their god damn grandkids the moment it so much as coughs up a warning. For the longest time it was notorious for doing this as the default error logging level.
I’m aware it’s cool to hate on PHP, but it has plenty of things to dislike without straight-up inventing nonsense.
Everyone else is just telling you to do things in a way that is different, and while they are correct (you should use a unit.d/systems script for this depending on your distro), I’m going to actually answer your question since I know sometimes you just need a quick and simple way.
Depending on your version of cron, it may support special statements instead of the * * * * * notation for time.
The one you want is @reboot. Replace all entries of the schedule syntax with that, including the @, and the command will be executed only once when the system boots up.
Use that to start a script that checks for network connectivity on a loop with a sleep statement. Break the loop when you have connectivity, then execute your command, and exit the script.
Don’t ignore the correct way though. You’re better off executing this as a systemd (or equivalent) script. It’s barely more effort, and has the benefit of some nice built in logging and integrations.
I have some bad news…
The effect you are describing is “viral load”; the degree to which a virus is present in the body. This is an indicator of how infectious you are. It is especially important for people with HIV to see if they are “safe” or need their medication adjusted.
However, an at-home test will not be a good indicator of this. These have too many variables such as the site that was swabbed, time delays from the various biological functions, how well you used the kit and even variability in the kit itself.
To properly test for viral load, a blood test should be used. I worked with a company that tested for viral load via expelled breath, and while this was a good indicator of infectiousness y/n, and was faster than a PCR, it was not more accurate.