Perl programming on my Mac OS

So, if I create a new folder and write new Perl scripts, run them and test them, there should be no problem. It seems crazy to think that COULD cause a problem.

One video I watched was pushing a unique download, perhaps of their newer/better version of Perl.

Not sure...

Thanks.

As long as you don't do something like open(OUT, ">/etc/fstab") or something else that will directly change system files, it will be fine.  The only thing I can think of that they might have been talking about was installing modules from CPAN into standard Perl lib dirs (which might be described as system files) but that shouldn't cause issues either - the only possible issue I can think of is if there is an old deprecated version installed and you install a new incompatible version of a module but I would hope the module would warn you about that or use a different name so it doesn't clobber the existing one (even if it does, there are ways to get the original version back).

Is there a firewall against any such stupid/beginner mistakes? If I shut down my Mac, I am dead.

If you only have one computer, you are almost guaranteed that it and you will die before your time.  You need a second computer at Least.  You may think that it is expensive.  Not as expensive as being suddenly out of business.

The simplest solution is to learn and write Perl as a normal user without sysadmin/root priveleges.  Then you should not be able to change system files even if you try.