This also demonstrates that the for variable is an alias, and not a copy:

my $foo = "foo";
for my $bar ($foo) 
{
    print "foo: $foo, ", \$foo, "\n";
    print "bar: $bar, ", \$bar, "\n";
    $bar = "bar";
    print "foo: $foo, ", \$foo, "\n";
    print "bar: $bar, ", \$bar, "\n";
}

print "foo: $foo, ", \$foo, "\n";
__OUTPUT__
foo: foo, SCALAR(0x18245f0)
bar: foo, SCALAR(0x18245f0)
foo: bar, SCALAR(0x18245f0)
bar: bar, SCALAR(0x18245f0)
foo: bar, SCALAR(0x18245f0)
__END__
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