I guess you can think of a local var as sort of like creating a stack of that variable. The local statement is like a "push" and when you exit the scope of the local, that is like a "pop". Rough analogy, but that is descriptive of the behavior.

#!usr/bin/perl
use warnings;
use strict;


our $x = 1;  #a package variable

{
   print "$x\n";  #prints 1
   local $x = 99;
   print "$x\n";  #prints 99
}

print "$x\n";  #prints 1, back to before the "local"
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:) in the OPs program, having  { local $/ ... } on the outside doesn't change the behavior of the program,

therefore no benefit is realized ... so the extra {local} is just extra typing (noise),

unless you add a name, like  sub StdinTriElReader{ local $/ = "\n\n\n"; ... } then its serves a purpose

:D:D:)

Oh, I see that post didn't use local $/= "\n\n\n"; in a some kind of read statement, I presume that was an oversight. Oops. A common use of local is so that you don't have to remember what say, $/ "was". Just re-define it with local and when scope finishes, it "pops" back to what it was. That was my main point.