or download this
my $string_upper = "BAR";
my $string_lower = "bar";
...
print " uc($string_lower) => (" , uc $string_lower, ")\n";
print "lcfirst($string_upper) => (" , lcfirst $string_upper, ")\n";
print "ucfirst($string_lower) => (" , ucfirst $string_lower, ")\n";