Perhaps this is obvious, but the behavior of this short code snippet confused me (actually it was buried in more complicated code that wasn't working for me), until I realized the potential indirect consequences of passing by reference... I pass it along for interest since at least for me the behavior was non-obvious... 
my $bar = "abc";
foo($bar);
$bar =~ /(.*)/;
my $val = $1;
foo($val);
foo($1);
print "|$1|$bar|\n";

sub foo
{
    print "$_[0]\n";
    $_[0] =~ /(.)/;
    print "$_[0]\n\n";
}

[download]
The result is: 
abc
abc

abc
abc

abc
a

|abc|abc|

[download]

In reply to Side effect of passing matched values by reference by puterboy

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