#/usr/bin/perl -w
use strict;

my %rh = (E=> *E, F=> *F, G=> *G);

{
    no strict 'refs';
    
    print "\n\n\$_ has a value, used as a hard reference\n";
    for (values %rh) {
        open  $_, ">test.txt" or die $!;
        print $_ "$_ This works\n";
        close $_  or die $!;
        open  $_, "<test.txt" or die $!; 
        print <$_>;
        close $_ or die $!;
        unlink "test.txt" or die $!;
    }
    
    print "\n\n\$_ has a value, used as a symbolic reference\n";
    for (keys %rh) {
        open  $_, ">test.txt" or die $!;
        print $_ "$_ This works\n";
        close $_  or die $!;
        open  $_, "<test.txt" or die $!; 
        print <$_>;
        close $_ or die $!;
        unlink "test.txt" or die $!;
    }
}

# and under strict....

print "\n\n\$_ has a value, used as a hard reference\n";
for (values %rh) {
    open  $_, ">test.txt" or die $!;
    print $_ "$_ This works\n";
    close $_  or die $!;
    open  $_, "<test.txt" or die $!; 
    print <$_>;
    close $_ or die $!;
    unlink "test.txt" or die $!;
}

print "\n\n\$_ has a value, used as a symbolic reference\n";
for (keys %rh) {
    open  $_, ">test.txt" or die $!;
    print $_ "$_ This works\n";
    close $_  or die $!;
    open  $_, "<test.txt" or die $!; 
    print <$_>;
    close $_ or die $!;
    unlink "test.txt" or die $!;
}