my $var = 'foo';

warn $var; # prints foo
by_val( $var );
warn $var; # prints foo
by_ref( \$var );
warn $var; # prints bar

sub by_ref{
  my $var_ref = shift;
  $$var_ref = 'bar';
}

sub by_val{
  my $var = shift;
  $var = 'bar';
}
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My understanding was that this is PbV and PbR respectively. Your post suggests that Perl is always PbR, so does that mean that my pass by value example is just allowing me to fake PbV? Or is the difference more of a technical, low level detail?

perl -e 'split//,q{john hurl, pest caretaker}and(map{print @_[$_]}(joi
+n(q{},map{sprintf(qq{%010u},$_)}(2**2*307*4993,5*101*641*5261,7*59*79
+*36997,13*17*71*45131,3**2*67*89*167*181))=~/\d{2}/g));'
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