How to predefine the mask?

[penguinkeeper]

Hashcat does have the ability to use custom charsets but currently only supports 4 custom charsets. There have been forks of Hashcat that raise it to 9 but it's not official code and you'd have to compile it yourself:
https://github.com/flaggx1/hashcat/tree/...m_charsets

For more info, check the "Custom Charsets" section of:
https://hashcat.net/wiki/doku.php?id=mask_attack