my $string_one = "foo bar baz";
my $string_two = "Foo bar baz";

ucfirst $string_one;
lcfirst $string_two;

print 'First letter is lowercase in $string_one' if $string_one =~ /^[a-z]/;
print 'First letter is lowercase in $string_two' if $string_two =~ /^[a-z]/;