What's the best way to write this regular expression?

[jkn]

Also unrelated to the OP, but a far superior Commnad line interface to
Windows is the (unhelpfully-named) 'console' program:

    http://sourceforge.net/projects/console/

This has tabbed windows, preset directory navigation, good copy/paste
facilities, the ability to configure different shells, etc etc.

Well worth a look.

    HTH
    J^n