P:\test>perldoc CHECK
No documentation found for "CHECK".

P:\test>perldoc /f CHECK
No documentation found for "/f".
No documentation found for "CHECK".

P:\test>perldoc -f CHECK
No documentation for perl function `CHECK' found

P:\test>perldoc -q CHECK
Found in C:\Perl\lib\pod\perlfaq4.pod
  How do I verify a credit card checksum?
    Get the Business::CreditCard module from CPAN.

Found in C:\Perl\lib\pod\perlfaq8.pod
  How do I check whether input is ready on the keyboard?
    The easiest way to do this is to read a key in nonblocking mode with the
    Term::ReadKey module from CPAN, passing it an argument of -1 to indicate
    not to block:

        use Term::ReadKey;

        ReadMode('cbreak');

        if (defined ($char = ReadKey(-1)) ) {
            # input was waiting and it was $char
        } else {
            # no input was waiting
        }

        ReadMode('normal');                  # restore normal tty settings

Found in C:\Perl\lib\pod\perlfaq9.pod
  How do I check a valid mail address?
    You can't, at least, not in real time. Bummer, eh?

    Without sending mail to the address and seeing whether there's a human
[SNIP]