Convert a whole directory recursively - WINDOWS

[John Jablonski]

In Windows OS command line find command is not compatible with example presented in readme. But the same can be done with command below:

FOR /f "tokens=*" %a in ('dir *.php /S/B') DO php convert.php %a -w

[Dariusz Rumiński]

@DoubleKing You could also use a php-cs-fixer (https://github.com/fabpot/PHP-CS-Fixer) using short_array_syntax fixer.

[Thomas Bachem]

Added to README.md in f4051c7, thanks!