# Not using strict, for demonstration.

sub at_top {
    print "Foo is: $foo\n";
}

# This is the body of the script, where a head-to-tail flow is in effect
my $foo = "I wanted this to be visible only for the body, not all of my subs!";

at_top();     # "Foo is: "
at_bottom();  # "Foo is: I wanted ..."

sub at_bottom {
    # We're in the same lexical scope!!
    print "Foo is: $foo\n";
}