What is your main OS besides the Amiga OSes and why?

[tone007]

BSD: % chmod 755 foo.tar.bz

Windows: CACLS filename /e /p {USERNAME}:{PERMISSION}

FTFY.  Seems a bit more flexible than the UNIX command as well, as you can specify an individual user as well as a group.

[tone007]

Tone007, you've moved from permissions now to ownership, which under UNIX is a totally separate concept. In UNIX it is accomplished via chown, in the following syntax:

% chown user:group $file

Windows NT lacks the difference here

No, ownership and permissions are separate in Windows as well.  CACLS manages permissions, TAKEOWN will allow you to manage ownership.