[vox-tech] lp vs lpadmin groups?

[Jeff Newmiller]

My Kubuntu system parallel port defaulted to ownership and permissions:

    crw-rw----  1 root lp 6, 0 2005-09-11 09:29 /dev/lp0

which seemed reasonable.  I was experiencing problems getting CUPS
to print to this, though, and Googling obtained the unsatisfactory
advice to "chmod 0777 /dev/lp0". Looking further, I finally noticed that
CUPS runs its filters as lp.lpadmin, and user lp did not come as a member
of group lp (!).

I figure the "best" solution is to make user "lp" a member of group "lp",
but I am curious now...

1) what are the intended purposes of groups "lp" and "lpadmin"?
2) would it be better to chown root.lpadmin /dev/lp0 (well, in my
case I would edit /etc/udev/permissions.d/udev.permissions)?
3) if "lpadmin" is intended to support queue maintenance and "lp"
is intended only for printer daemons, how is printer access
supposed to be controlled for users who just want to print?
or, if group "lp" is for anyone who can print, then how to distinguish
between users and queue administrators?

I have to admit that CUPS seems much more userfriendly than lpr did.

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